# Struct bytes::BytesMut [−] [src]

    pub struct BytesMut { /* fields omitted */ }

A unique reference to a contiguous slice of memory.

`BytesMut` represents a unique view into a potentially shared memory region. Given the uniqueness guarantee, owners of `BytesMut` handles are able to mutate the memory.

`BytesMut` can be thought of as containing a `buf: Arc<Vec<u8>>`, an offset into `buf`, a slice length, and a guarantee that no other `BytesMut` for the same `buf` overlaps with its slice. That guarantee means that a write lock is not required.

# Growth

`BytesMut`’s `BufMut` implementation will implicitly grow its buffer as necessary. However, explicitly reserving the required space up-front before a series of inserts will be more efficient.

# Examples

    use bytes::{BytesMut, BufMut};

    let mut buf = BytesMut::with_capacity(64);

    buf.put_u8(b'h');
    buf.put_u8(b'e');
    buf.put(&b"llo"[..]);

    assert_eq!(&buf[..], b"hello");

    // Freeze the buffer so that it can be shared
    let a = buf.freeze();

    // This does not allocate, instead `b` points to the same memory.
    let b = a.clone();

    assert_eq!(&a[..], b"hello");
    assert_eq!(&b[..], b"hello");

## Implementations

### `impl BytesMut` [src]

#### `pub fn with_capacity(capacity: usize) -> BytesMut` [src]

Creates a new `BytesMut` with the specified capacity.

The returned `BytesMut` will be able to hold at least `capacity` bytes without reallocating.

It is important to note that this function does not specify the length of the returned `BytesMut`, but only the capacity.

# Examples

    use bytes::{BytesMut, BufMut};

    let mut bytes = BytesMut::with_capacity(64);

    // `bytes` contains no data, even though there is capacity
    assert_eq!(bytes.len(), 0);

    bytes.put(&b"hello world"[..]);

    assert_eq!(&bytes[..], b"hello world");

#### `pub fn new() -> BytesMut` [src]

Creates a new `BytesMut` with default capacity.

Resulting object has length 0 and unspecified capacity. This function does not allocate.

# Examples

    use bytes::{BytesMut, BufMut};

    let mut bytes = BytesMut::new();

    assert_eq!(0, bytes.len());

    bytes.reserve(2);
    bytes.put_slice(b"xy");

    assert_eq!(&b"xy"[..], &bytes[..]);

#### `pub fn len(&self) -> usize` [src]

Returns the number of bytes contained in this `BytesMut`.

# Examples

    use bytes::BytesMut;

    let b = BytesMut::from(&b"hello"[..]);
    assert_eq!(b.len(), 5);

#### `pub fn is_empty(&self) -> bool` [src]

Returns true if the `BytesMut` has a length of 0.

# Examples

    use bytes::BytesMut;

    let b = BytesMut::with_capacity(64);
    assert!(b.is_empty());

#### `pub fn capacity(&self) -> usize` [src]

Returns the number of bytes the `BytesMut` can hold without reallocating.

# Examples

    use bytes::BytesMut;

    let b = BytesMut::with_capacity(64);
    assert_eq!(b.capacity(), 64);

#### `pub fn freeze(self) -> Bytes` [src]

Converts `self` into an immutable `Bytes`.

The conversion is zero cost and is used to indicate that the slice referenced by the handle will no longer be mutated. Once the conversion is done, the handle can be cloned and shared across threads.

# Examples

    use bytes::{BytesMut, BufMut};
    use std::thread;

    let mut b = BytesMut::with_capacity(64);
    b.put(&b"hello world"[..]);
    let b1 = b.freeze();
    let b2 = b1.clone();

    let th = thread::spawn(move || {
        assert_eq!(&b1[..], b"hello world");
    });

    assert_eq!(&b2[..], b"hello world");
    th.join().unwrap();

#### `#[must_use = "consider BytesMut::truncate if you don't need the other half"]pub fn split_off(&mut self, at: usize) -> BytesMut` [src]

Splits the bytes into two at the given index.

Afterwards `self` contains elements `[0, at)`, and the returned `BytesMut` contains elements `[at, capacity)`.

This is an `O(1)` operation that just increases the reference count and sets a few indices.

# Examples

    use bytes::BytesMut;

    let mut a = BytesMut::from(&b"hello world"[..]);
    let mut b = a.split_off(5);

    a[0] = b'j';
    b[0] = b'!';

    assert_eq!(&a[..], b"jello");
    assert_eq!(&b[..], b"!world");

# Panics

Panics if `at > capacity`.

#### `#[must_use = "consider BytesMut::advance(len()) if you don't need the other half"]pub fn split(&mut self) -> BytesMut` [src]

Removes the bytes from the current view, returning them in a new `BytesMut` handle.

Afterwards, `self` will be empty, but will retain any additional capacity that it had before the operation. This is identical to `self.split_to(self.len())`.

This is an `O(1)` operation that just increases the reference count and sets a few indices.

# Examples

    use bytes::{BytesMut, BufMut};

    let mut buf = BytesMut::with_capacity(1024);
    buf.put(&b"hello world"[..]);

    let other = buf.split();

    assert!(buf.is_empty());
    assert_eq!(1013, buf.capacity());

    assert_eq!(other, b"hello world"[..]);

#### `#[must_use = "consider BytesMut::advance if you don't need the other half"]pub fn split_to(&mut self, at: usize) -> BytesMut` [src]

Splits the buffer into two at the given index.

Afterwards `self` contains elements `[at, len)`, and the returned `BytesMut` contains elements `[0, at)`.

This is an `O(1)` operation that just increases the reference count and sets a few indices.

# Examples

    use bytes::BytesMut;

    let mut a = BytesMut::from(&b"hello world"[..]);
    let mut b = a.split_to(5);

    a[0] = b'!';
    b[0] = b'j';

    assert_eq!(&a[..], b"!world");
    assert_eq!(&b[..], b"jello");

# Panics

Panics if `at > len`.

#### `pub fn truncate(&mut self, len: usize)` [src]

Shortens the buffer, keeping the first `len` bytes and dropping the rest.

If `len` is greater than the buffer’s current length, this has no effect.

The `split_off` method can emulate `truncate`, but this causes the excess bytes to be returned instead of dropped.

# Examples

    use bytes::BytesMut;

    let mut buf = BytesMut::from(&b"hello world"[..]);
    buf.truncate(5);
    assert_eq!(buf, b"hello"[..]);

#### `pub fn clear(&mut self)` [src]

Clears the buffer, removing all data.

# Examples

    use bytes::BytesMut;

    let mut buf = BytesMut::from(&b"hello world"[..]);
    buf.clear();
    assert!(buf.is_empty());

#### `pub fn resize(&mut self, new_len: usize, value: u8)` [src]

Resizes the buffer so that `len` is equal to `new_len`.

If `new_len` is greater than `len`, the buffer is extended by the difference with each additional byte set to `value`. If `new_len` is less than `len`, the buffer is simply truncated.

# Examples

    use bytes::BytesMut;

    let mut buf = BytesMut::new();

    buf.resize(3, 0x1);
    assert_eq!(&buf[..], &[0x1, 0x1, 0x1]);

    buf.resize(2, 0x2);
    assert_eq!(&buf[..], &[0x1, 0x1]);

    buf.resize(4, 0x3);
    assert_eq!(&buf[..], &[0x1, 0x1, 0x3, 0x3]);

#### `pub unsafe fn set_len(&mut self, len: usize)` [src]

Sets the length of the buffer.

This will explicitly set the size of the buffer without actually modifying the data, so it is up to the caller to ensure that the data has been initialized.

# Examples

    use bytes::BytesMut;

    let mut b = BytesMut::from(&b"hello world"[..]);

    unsafe {
        b.set_len(5);
    }

    assert_eq!(&b[..], b"hello");

    unsafe {
        b.set_len(11);
    }

    assert_eq!(&b[..], b"hello world");

#### `pub fn reserve(&mut self, additional: usize)` [src]

Reserves capacity for at least `additional` more bytes to be inserted into the given `BytesMut`.

More than `additional` bytes may be reserved in order to avoid frequent reallocations. A call to `reserve` may result in an allocation.

Before allocating new buffer space, the function will attempt to reclaim space in the existing buffer. If the current handle references a small view in the original buffer and all other handles have been dropped, and the requested capacity is less than or equal to the existing buffer’s capacity, then the current view will be copied to the front of the buffer and the handle will take ownership of the full buffer.

# Examples

In the following example, a new buffer is allocated.

    use bytes::BytesMut;

    let mut buf = BytesMut::from(&b"hello"[..]);
    buf.reserve(64);
    assert!(buf.capacity() >= 69);

In the following example, the existing buffer is reclaimed.

    use bytes::{BytesMut, BufMut};

    let mut buf = BytesMut::with_capacity(128);
    buf.put(&[0; 64][..]);

    let ptr = buf.as_ptr();
    let other = buf.split();

    assert!(buf.is_empty());
    assert_eq!(buf.capacity(), 64);

    drop(other);
    buf.reserve(128);

    assert_eq!(buf.capacity(), 128);
    assert_eq!(buf.as_ptr(), ptr);

# Panics

Panics if the new capacity overflows `usize`.

#### `pub fn extend_from_slice(&mut self, extend: &[u8])` [src]

Appends given bytes to this `BytesMut`.

If this `BytesMut` object does not have enough capacity, it is resized first.

# Examples

    use bytes::BytesMut;

    let mut buf = BytesMut::with_capacity(0);
    buf.extend_from_slice(b"aaabbb");
    buf.extend_from_slice(b"cccddd");

    assert_eq!(b"aaabbbcccddd", &buf[..]);

#### `pub fn unsplit(&mut self, other: BytesMut)` [src]

Absorbs a `BytesMut` that was previously split off.

If the two `BytesMut` objects were previously contiguous, i.e., if `other` was created by calling `split_off` on this `BytesMut`, then this is an `O(1)` operation that just decreases a reference count and sets a few indices. Otherwise this method degenerates to `self.extend_from_slice(other.as_ref())`.

# Examples

    use bytes::BytesMut;

    let mut buf = BytesMut::with_capacity(64);
    buf.extend_from_slice(b"aaabbbcccddd");

    let split = buf.split_off(6);
    assert_eq!(b"aaabbb", &buf[..]);
    assert_eq!(b"cccddd", &split[..]);

    buf.unsplit(split);
    assert_eq!(b"aaabbbcccddd", &buf[..]);

## Methods from Deref<Target = [ u8 ]>

#### `pub const fn len(&self) -> usize` 1.0.0 (const: 1.32.0) [src]

Returns the number of elements in the slice.

# Examples

    let a = [1, 2, 3];
    assert_eq!(a.len(), 3);

#### `pub const fn is_empty(&self) -> bool` 1.0.0 (const: 1.32.0) [src]

Returns `true` if the slice has a length of 0.

# Examples

    let a = [1, 2, 3];
    assert!(!a.is_empty());

#### `pub fn first(&self) -> Option<&T>`1.0.0 [src]

Returns the first element of the slice, or `None` if it is empty.

# Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&10), v.first());

    let w: &[i32] = &[];
    assert_eq!(None, w.first());

#### `pub fn first_mut(&mut self) -> Option<&mut T>`1.0.0 [src]

Returns a mutable pointer to the first element of the slice, or `None` if it is empty.

# Examples

    let x = &mut [0, 1, 2];

    if let Some(first) = x.first_mut() {
        *first = 5;
    }
    assert_eq!(x, &[5, 1, 2]);

#### `pub fn split_first(&self) -> Option<(&T, &[T])>`1.5.0 [src]

Returns the first and all the rest of the elements of the slice, or `None` if it is empty.

# Examples

    let x = &[0, 1, 2];

    if let Some((first, elements)) = x.split_first() {
        assert_eq!(first, &0);
        assert_eq!(elements, &[1, 2]);
    }

#### `pub fn split_first_mut(&mut self) -> Option<(&mut T, &mut [T])>`1.5.0 [src]

Returns the first and all the rest of the elements of the slice, or `None` if it is empty.

# Examples

    let x = &mut [0, 1, 2];

    if let Some((first, elements)) = x.split_first_mut() {
        *first = 3;
        elements[0] = 4;
        elements[1] = 5;
    }
    assert_eq!(x, &[3, 4, 5]);

#### `pub fn split_last(&self) -> Option<(&T, &[T])>`1.5.0 [src]

Returns the last and all the rest of the elements of the slice, or `None` if it is empty.

# Examples

    let x = &[0, 1, 2];

    if let Some((last, elements)) = x.split_last() {
        assert_eq!(last, &2);
        assert_eq!(elements, &[0, 1]);
    }

#### `pub fn split_last_mut(&mut self) -> Option<(&mut T, &mut [T])>`1.5.0 [src]

Returns the last and all the rest of the elements of the slice, or `None` if it is empty.

# Examples

    let x = &mut [0, 1, 2];

    if let Some((last, elements)) = x.split_last_mut() {
        *last = 3;
        elements[0] = 4;
        elements[1] = 5;
    }
    assert_eq!(x, &[4, 5, 3]);

#### `pub fn last(&self) -> Option<&T>`1.0.0 [src]

Returns the last element of the slice, or `None` if it is empty.

# Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&30), v.last());

    let w: &[i32] = &[];
    assert_eq!(None, w.last());

#### `pub fn last_mut(&mut self) -> Option<&mut T>`1.0.0 [src]

Returns a mutable pointer to the last item in the slice.

# Examples

    let x = &mut [0, 1, 2];

    if let Some(last) = x.last_mut() {
        *last = 10;
    }
    assert_eq!(x, &[0, 1, 10]);

#### `pub fn get<I>(&self, index: I) -> Option<&<I as SliceIndex<[T]>>::Output> where
I: SliceIndex<[T]>,` 1.0.0 [src]

Returns a reference to an element or subslice depending on the type of index.

- If given a position, returns a reference to the element at that position or `None` if out of bounds.
- If given a range, returns the subslice corresponding to that range, or `None` if out of bounds.

# Examples

    let v = [10, 40, 30];
    assert_eq!(Some(&40), v.get(1));
    assert_eq!(Some(&[10, 40][..]), v.get(0..2));
    assert_eq!(None, v.get(3));
    assert_eq!(None, v.get(0..4));

#### `pub fn get_mut<I>(
&mut self,
index: I
) -> Option<&mut <I as SliceIndex<[T]>>::Output> where
I: SliceIndex<[T]>,` 1.0.0 [src]

Returns a mutable reference to an element or subslice depending on the type of index (see `get`) or `None` if the index is out of bounds.

# Examples

    let x = &mut [0, 1, 2];

    if let Some(elem) = x.get_mut(1) {
        *elem = 42;
    }
    assert_eq!(x, &[0, 42, 2]);

#### `pub unsafe fn get_unchecked<I>(
&self,
index: I
) -> &<I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,` 1.0.0 [src]

Returns a reference to an element or subslice, without doing bounds checking.

For a safe alternative see `get`.

# Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

# Examples

    let x = &[1, 2, 4];

    unsafe {
        assert_eq!(x.get_unchecked(1), &2);
    }

#### `pub unsafe fn get_unchecked_mut<I>(
&mut self,
index: I
) -> &mut <I as SliceIndex<[T]>>::Output where
I: SliceIndex<[T]>,` 1.0.0 [src]

Returns a mutable reference to an element or subslice, without doing bounds checking.

For a safe alternative see `get_mut`.

# Safety

Calling this method with an out-of-bounds index is undefined behavior even if the resulting reference is not used.

# Examples

    let x = &mut [1, 2, 4];

    unsafe {
        let elem = x.get_unchecked_mut(1);
        *elem = 13;
    }
    assert_eq!(x, &[1, 13, 4]);

#### `pub const fn as_ptr(&self) -> *const T` 1.0.0 (const: 1.32.0) [src]

Returns a raw pointer to the slice’s buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.

The caller must also ensure that the memory the pointer (non-transitively) points to is never written to (except inside an `UnsafeCell`) using this pointer or any pointer derived from it. If you need to mutate the contents of the slice, use `as_mut_ptr`.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

# Examples

    let x = &[1, 2, 4];
    let x_ptr = x.as_ptr();

    unsafe {
        for i in 0..x.len() {
            assert_eq!(x.get_unchecked(i), &*x_ptr.add(i));
        }
    }

#### `pub const fn as_mut_ptr(&mut self) -> *mut T` 1.0.0 [src]

Returns an unsafe mutable pointer to the slice’s buffer.

The caller must ensure that the slice outlives the pointer this function returns, or else it will end up pointing to garbage.

Modifying the container referenced by this slice may cause its buffer to be reallocated, which would also make any pointers to it invalid.

# Examples

    let x = &mut [1, 2, 4];
    let x_ptr = x.as_mut_ptr();

    unsafe {
        for i in 0..x.len() {
            *x_ptr.add(i) += 2;
        }
    }
    assert_eq!(x, &[3, 4, 6]);

#### `pub const fn as_ptr_range(&self) -> Range<*const T>`1.48.0 [src]

Returns the two raw pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See `as_ptr` for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

It can also be useful to check if a pointer to an element refers to an element of this slice:

    let a = [1, 2, 3];
    let x = &a[1] as *const _;
    let y = &5 as *const _;

    assert!(a.as_ptr_range().contains(&x));
    assert!(!a.as_ptr_range().contains(&y));

#### `pub const fn as_mut_ptr_range(&mut self) -> Range<*mut T>`1.48.0 [src]

Returns the two unsafe mutable pointers spanning the slice.

The returned range is half-open, which means that the end pointer points one past the last element of the slice. This way, an empty slice is represented by two equal pointers, and the difference between the two pointers represents the size of the slice.

See `as_mut_ptr` for warnings on using these pointers. The end pointer requires extra caution, as it does not point to a valid element in the slice.

This function is useful for interacting with foreign interfaces which use two pointers to refer to a range of elements in memory, as is common in C++.

#### `pub fn swap(&mut self, a: usize, b: usize)`1.0.0 [src]

Swaps two elements in the slice.

# Arguments

- a - The index of the first element
- b - The index of the second element

# Panics

Panics if `a` or `b` are out of bounds.

# Examples

    let mut v = ["a", "b", "c", "d"];
    v.swap(1, 3);
    assert!(v == ["a", "d", "c", "b"]);

#### `pub fn reverse(&mut self)`1.0.0 [src]

Reverses the order of elements in the slice, in place.

# Examples

    let mut v = [1, 2, 3];
    v.reverse();
    assert!(v == [3, 2, 1]);

#### `pub fn iter(&self) -> Iter<'_, T>`1.0.0 [src]

Returns an iterator over the slice.

# Examples

    let x = &[1, 2, 4];
    let mut iterator = x.iter();

    assert_eq!(iterator.next(), Some(&1));
    assert_eq!(iterator.next(), Some(&2));
    assert_eq!(iterator.next(), Some(&4));
    assert_eq!(iterator.next(), None);

#### `pub fn iter_mut(&mut self) -> IterMut<'_, T>`1.0.0 [src]

Returns an iterator that allows modifying each value.

# Examples

    let x = &mut [1, 2, 4];
    for elem in x.iter_mut() {
        *elem += 2;
    }
    assert_eq!(x, &[3, 4, 6]);

#### `pub fn windows(&self, size: usize) -> Windows<'_, T>`1.0.0 [src]

Returns an iterator over all contiguous windows of length `size`. The windows overlap. If the slice is shorter than `size`, the iterator returns no values.

# Panics

Panics if `size` is 0.

# Examples

    let slice = ['r', 'u', 's', 't'];
    let mut iter = slice.windows(2);
    assert_eq!(iter.next().unwrap(), &['r', 'u']);
    assert_eq!(iter.next().unwrap(), &['u', 's']);
    assert_eq!(iter.next().unwrap(), &['s', 't']);
    assert!(iter.next().is_none());

If the slice is shorter than `size`:

    let slice = ['f', 'o', 'o'];
    let mut iter = slice.windows(4);
    assert!(iter.next().is_none());

#### `pub fn chunks(&self, chunk_size: usize) -> Chunks<'_, T>`1.0.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `chunks_exact` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `rchunks` for the same iterator but starting at the end of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.chunks(2);
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert_eq!(iter.next().unwrap(), &['m']);
    assert!(iter.next().is_none());

#### `pub fn chunks_mut(&mut self, chunk_size: usize) -> ChunksMut<'_, T>`1.0.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `chunks_exact_mut` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `rchunks_mut` for the same iterator but starting at the end of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.chunks_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 3]);

#### `pub fn chunks_exact(&self, chunk_size: usize) -> ChunksExact<'_, T>`1.31.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks`.

See `chunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `rchunks_exact` for the same iterator but starting at the end of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.chunks_exact(2);
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['m']);

#### `pub fn chunks_exact_mut(&mut self, chunk_size: usize) -> ChunksExactMut<'_, T>`1.31.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `into_remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks_mut`.

See `chunks_mut` for a variant of this iterator that also returns the remainder as a smaller chunk, and `rchunks_exact_mut` for the same iterator but starting at the end of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.chunks_exact_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 0]);

#### `pub unsafe fn as_chunks_unchecked<const N: usize>(&self) -> &[[T; N]]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks`)

Splits the slice into a slice of `N`-element arrays, assuming that there’s no remainder.

# Safety

This may only be called when

- The slice splits exactly into `N`-element chunks (aka `self.len() % N == 0`).
- `N != 0`.

# Examples

    #![feature(slice_as_chunks)]
    let slice: &[char] = &['l', 'o', 'r', 'e', 'm', '!'];
    let chunks: &[[char; 1]] =
        // SAFETY: 1-element chunks never have remainder
        unsafe { slice.as_chunks_unchecked() };
    assert_eq!(chunks, &[['l'], ['o'], ['r'], ['e'], ['m'], ['!']]);
    let chunks: &[[char; 3]] =
        // SAFETY: The slice length (6) is a multiple of 3
        unsafe { slice.as_chunks_unchecked() };
    assert_eq!(chunks, &[['l', 'o', 'r'], ['e', 'm', '!']]);

    // These would be unsound:
    // let chunks: &[[_; 5]] = slice.as_chunks_unchecked() // The slice length is not a multiple of 5
    // let chunks: &[[_; 0]] = slice.as_chunks_unchecked() // Zero-length chunks are never allowed

#### `pub fn as_chunks<const N: usize>(&self) -> (&[[T; N]], &[T])` [src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks`)

Splits the slice into a slice of `N`-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than `N`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(slice_as_chunks)]
    let slice = ['l', 'o', 'r', 'e', 'm'];
    let (chunks, remainder) = slice.as_chunks();
    assert_eq!(chunks, &[['l', 'o'], ['r', 'e']]);
    assert_eq!(remainder, &['m']);

#### `pub fn as_rchunks<const N: usize>(&self) -> (&[T], &[[T; N]])` [src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks`)

Splits the slice into a slice of `N`-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than `N`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(slice_as_chunks)]
    let slice = ['l', 'o', 'r', 'e', 'm'];
    let (remainder, chunks) = slice.as_rchunks();
    assert_eq!(remainder, &['l']);
    assert_eq!(chunks, &[['o', 'r'], ['e', 'm']]);

#### `pub fn array_chunks<const N: usize>(&self) -> ArrayChunks<'_, T, N>` [src]

🔬 This is a nightly-only experimental API. (`array_chunks`)

Returns an iterator over `N` elements of the slice at a time, starting at the beginning of the slice.

The chunks are array references and do not overlap. If `N` does not divide the length of the slice, then the last up to `N-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

This method is the const generic equivalent of `chunks_exact`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(array_chunks)]
    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.array_chunks();
    assert_eq!(iter.next().unwrap(), &['l', 'o']);
    assert_eq!(iter.next().unwrap(), &['r', 'e']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['m']);

#### `pub unsafe fn as_chunks_unchecked_mut<const N: usize>(
&mut self
) -> &mut [[T; N]]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks`)

Splits the slice into a slice of `N`-element arrays, assuming that there’s no remainder.

# Safety

This may only be called when

- The slice splits exactly into `N`-element chunks (aka `self.len() % N == 0`).
- `N != 0`.

# Examples

    #![feature(slice_as_chunks)]
    let slice: &mut [char] = &mut ['l', 'o', 'r', 'e', 'm', '!'];
    let chunks: &mut [[char; 1]] =
        // SAFETY: 1-element chunks never have remainder
        unsafe { slice.as_chunks_unchecked_mut() };
    chunks[0] = ['L'];
    assert_eq!(chunks, &[['L'], ['o'], ['r'], ['e'], ['m'], ['!']]);
    let chunks: &mut [[char; 3]] =
        // SAFETY: The slice length (6) is a multiple of 3
        unsafe { slice.as_chunks_unchecked_mut() };
    chunks[1] = ['a', 'x', '?'];
    assert_eq!(slice, &['L', 'o', 'r', 'a', 'x', '?']);

    // These would be unsound:
    // let chunks: &[[_; 5]] = slice.as_chunks_unchecked_mut() // The slice length is not a multiple of 5
    // let chunks: &[[_; 0]] = slice.as_chunks_unchecked_mut() // Zero-length chunks are never allowed

#### `pub fn as_chunks_mut<const N: usize>(&mut self) -> (&mut [[T; N]], &mut [T])` [src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks`)

Splits the slice into a slice of `N`-element arrays, starting at the beginning of the slice, and a remainder slice with length strictly less than `N`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(slice_as_chunks)]
    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    let (chunks, remainder) = v.as_chunks_mut();
    remainder[0] = 9;
    for chunk in chunks {
        *chunk = [count; 2];
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 9]);

#### `pub fn as_rchunks_mut<const N: usize>(&mut self) -> (&mut [T], &mut [[T; N]])` [src]

🔬 This is a nightly-only experimental API. (`slice_as_chunks`)

Splits the slice into a slice of `N`-element arrays, starting at the end of the slice, and a remainder slice with length strictly less than `N`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(slice_as_chunks)]
    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    let (remainder, chunks) = v.as_rchunks_mut();
    remainder[0] = 9;
    for chunk in chunks {
        *chunk = [count; 2];
        count += 1;
    }
    assert_eq!(v, &[9, 1, 1, 2, 2]);

#### `pub fn array_chunks_mut<const N: usize>(&mut self) -> ArrayChunksMut<'_, T, N>` [src]

🔬 This is a nightly-only experimental API. (`array_chunks`)

Returns an iterator over `N` elements of the slice at a time, starting at the beginning of the slice.

The chunks are mutable array references and do not overlap. If `N` does not divide the length of the slice, then the last up to `N-1` elements will be omitted and can be retrieved from the `into_remainder` function of the iterator.

This method is the const generic equivalent of `chunks_exact_mut`.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(array_chunks)]
    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.array_chunks_mut() {
        *chunk = [count; 2];
        count += 1;
    }
    assert_eq!(v, &[1, 1, 2, 2, 0]);

#### `pub fn array_windows<const N: usize>(&self) -> ArrayWindows<'_, T, N>` [src]

🔬 This is a nightly-only experimental API. (`array_windows`)

Returns an iterator over overlapping windows of `N` elements of a slice, starting at the beginning of the slice.

This is the const generic equivalent of `windows`.

If `N` is greater than the size of the slice, it will return no windows.

# Panics

Panics if `N` is 0. This check will most probably get changed to a compile time error before this method gets stabilized.

# Examples

    #![feature(array_windows)]
    let slice = [0, 1, 2, 3];
    let mut iter = slice.array_windows();
    assert_eq!(iter.next().unwrap(), &[0, 1]);
    assert_eq!(iter.next().unwrap(), &[1, 2]);
    assert_eq!(iter.next().unwrap(), &[2, 3]);
    assert!(iter.next().is_none());

#### `pub fn rchunks(&self, chunk_size: usize) -> RChunks<'_, T>`1.31.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `rchunks_exact` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `chunks` for the same iterator but starting at the beginning of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.rchunks(2);
    assert_eq!(iter.next().unwrap(), &['e', 'm']);
    assert_eq!(iter.next().unwrap(), &['o', 'r']);
    assert_eq!(iter.next().unwrap(), &['l']);
    assert!(iter.next().is_none());

#### `pub fn rchunks_mut(&mut self, chunk_size: usize) -> RChunksMut<'_, T>`1.31.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last chunk will not have length `chunk_size`.

See `rchunks_exact_mut` for a variant of this iterator that returns chunks of always exactly `chunk_size` elements, and `chunks_mut` for the same iterator but starting at the beginning of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.rchunks_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[3, 2, 2, 1, 1]);

#### `pub fn rchunks_exact(&self, chunk_size: usize) -> RChunksExact<'_, T>`1.31.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are slices and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks`.

See `rchunks` for a variant of this iterator that also returns the remainder as a smaller chunk, and `chunks_exact` for the same iterator but starting at the beginning of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let slice = ['l', 'o', 'r', 'e', 'm'];
    let mut iter = slice.rchunks_exact(2);
    assert_eq!(iter.next().unwrap(), &['e', 'm']);
    assert_eq!(iter.next().unwrap(), &['o', 'r']);
    assert!(iter.next().is_none());
    assert_eq!(iter.remainder(), &['l']);

#### `pub fn rchunks_exact_mut(&mut self, chunk_size: usize) -> RChunksExactMut<'_, T>`1.31.0 [src]

Returns an iterator over `chunk_size` elements of the slice at a time, starting at the end of the slice.

The chunks are mutable slices, and do not overlap. If `chunk_size` does not divide the length of the slice, then the last up to `chunk_size-1` elements will be omitted and can be retrieved from the `into_remainder` function of the iterator.

Due to each chunk having exactly `chunk_size` elements, the compiler can often optimize the resulting code better than in the case of `chunks_mut`.

See `rchunks_mut` for a variant of this iterator that also returns the remainder as a smaller chunk, and `chunks_exact_mut` for the same iterator but starting at the beginning of the slice.

# Panics

Panics if `chunk_size` is 0.

# Examples

    let v = &mut [0, 0, 0, 0, 0];
    let mut count = 1;

    for chunk in v.rchunks_exact_mut(2) {
        for elem in chunk.iter_mut() {
            *elem += count;
        }
        count += 1;
    }
    assert_eq!(v, &[0, 2, 2, 1, 1]);

#### `pub fn group_by<F>(&self, pred: F) -> GroupBy<'_, T, F> where
F: FnMut(&T, &T) -> bool,` [src]

🔬 This is a nightly-only experimental API. (`slice_group_by`)

Returns an iterator over the slice producing non-overlapping runs of elements using the predicate to separate them.

The predicate is called on two elements following themselves, it means the predicate is called on `slice[0]` and `slice[1]` then on `slice[1]` and `slice[2]` and so on.

# Examples

    #![feature(slice_group_by)]

    let slice = &[1, 1, 1, 3, 3, 2, 2, 2];

    let mut iter = slice.group_by(|a, b| a == b);

    assert_eq!(iter.next(), Some(&[1, 1, 1][..]));
    assert_eq!(iter.next(), Some(&[3, 3][..]));
    assert_eq!(iter.next(), Some(&[2, 2, 2][..]));
    assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

    #![feature(slice_group_by)]

    let slice = &[1, 1, 2, 3, 2, 3, 2, 3, 4];

    let mut iter = slice.group_by(|a, b| a <= b);

    assert_eq!(iter.next(), Some(&[1, 1, 2, 3][..]));
    assert_eq!(iter.next(), Some(&[2, 3][..]));
    assert_eq!(iter.next(), Some(&[2, 3, 4][..]));
    assert_eq!(iter.next(), None);

#### `pub fn group_by_mut<F>(&mut self, pred: F) -> GroupByMut<'_, T, F> where
F: FnMut(&T, &T) -> bool,` [src]

🔬 This is a nightly-only experimental API. (`slice_group_by`)

Returns an iterator over the slice producing non-overlapping mutable runs of elements using the predicate to separate them.

The predicate is called on two elements following themselves, it means the predicate is called on `slice[0]` and `slice[1]` then on `slice[1]` and `slice[2]` and so on.

# Examples

    #![feature(slice_group_by)]

    let slice = &mut [1, 1, 1, 3, 3, 2, 2, 2];

    let mut iter = slice.group_by_mut(|a, b| a == b);

    assert_eq!(iter.next(), Some(&mut [1, 1, 1][..]));
    assert_eq!(iter.next(), Some(&mut [3, 3][..]));
    assert_eq!(iter.next(), Some(&mut [2, 2, 2][..]));
    assert_eq!(iter.next(), None);

This method can be used to extract the sorted subslices:

    #![feature(slice_group_by)]

    let slice = &mut [1, 1, 2, 3, 2, 3, 2, 3, 4];

    let mut iter = slice.group_by_mut(|a, b| a <= b);

    assert_eq!(iter.next(), Some(&mut [1, 1, 2, 3][..]));
    assert_eq!(iter.next(), Some(&mut [2, 3][..]));
    assert_eq!(iter.next(), Some(&mut [2, 3, 4][..]));
    assert_eq!(iter.next(), None);

#### `pub fn split_at(&self, mid: usize) -> (&[T], &[T])`1.0.0 [src]

Divides one slice into two at an index.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

# Panics

Panics if `mid > len`.

# Examples

    let v = [1, 2, 3, 4, 5, 6];

    {
       let (left, right) = v.split_at(0);
       assert_eq!(left, []);
       assert_eq!(right, [1, 2, 3, 4, 5, 6]);
    }

    {
        let (left, right) = v.split_at(2);
        assert_eq!(left, [1, 2]);
        assert_eq!(right, [3, 4, 5, 6]);
    }

    {
        let (left, right) = v.split_at(6);
        assert_eq!(left, [1, 2, 3, 4, 5, 6]);
        assert_eq!(right, []);
    }

#### `pub fn split_at_mut(&mut self, mid: usize) -> (&mut [T], &mut [T])`1.0.0 [src]

Divides one mutable slice into two at an index.

The first will contain all indices from `[0, mid)` (excluding the index `mid` itself) and the second will contain all indices from `[mid, len)` (excluding the index `len` itself).

# Panics

Panics if `mid > len`.

# Examples

    let mut v = [1, 0, 3, 0, 5, 6];
    let (left, right) = v.split_at_mut(2);
    assert_eq!(left, [1, 0]);
    assert_eq!(right, [3, 0, 5, 6]);
    left[1] = 2;
    right[1] = 4;
    assert_eq!(v, [1, 2, 3, 4, 5, 6]);

#### `pub fn split<F>(&self, pred: F) -> Split<'_, T, F> where
F: FnMut(&T) -> bool,` 1.0.0 [src]

Returns an iterator over subslices separated by elements that match `pred`. The matched element is not contained in the subslices.

# Examples

    let slice = [10, 40, 33, 20];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

If the first element is matched, an empty slice will be the first item returned by the iterator. Similarly, if the last element in the slice is matched, an empty slice will be the last item returned by the iterator:

    let slice = [10, 40, 33];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40]);
    assert_eq!(iter.next().unwrap(), &[]);
    assert!(iter.next().is_none());

If two matched elements are directly adjacent, an empty slice will be present between them:

    let slice = [10, 6, 33, 20];
    let mut iter = slice.split(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10]);
    assert_eq!(iter.next().unwrap(), &[]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

#### `pub fn split_mut<F>(&mut self, pred: F) -> SplitMut<'_, T, F> where
F: FnMut(&T) -> bool,` 1.0.0 [src]

Returns an iterator over mutable subslices separated by elements that match `pred`. The matched element is not contained in the subslices.

# Examples

    let mut v = [10, 40, 30, 20, 60, 50];

    for group in v.split_mut(|num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(v, [1, 40, 30, 1, 60, 1]);

#### `pub fn split_inclusive<F>(&self, pred: F) -> SplitInclusive<'_, T, F> where
F: FnMut(&T) -> bool,` 1.51.0 [src]

Returns an iterator over subslices separated by elements that match `pred`. The matched element is contained in the end of the previous subslice as a terminator.

# Examples

    let slice = [10, 40, 33, 20];
    let mut iter = slice.split_inclusive(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
    assert_eq!(iter.next().unwrap(), &[20]);
    assert!(iter.next().is_none());

If the last element of the slice is matched, that element will be considered the terminator of the preceding slice. That slice will be the last item returned by the iterator.

    let slice = [3, 10, 40, 33];
    let mut iter = slice.split_inclusive(|num| num % 3 == 0);

    assert_eq!(iter.next().unwrap(), &[3]);
    assert_eq!(iter.next().unwrap(), &[10, 40, 33]);
    assert!(iter.next().is_none());

#### `pub fn split_inclusive_mut<F>(&mut self, pred: F) -> SplitInclusiveMut<'_, T, F> where
F: FnMut(&T) -> bool,` 1.51.0 [src]

Returns an iterator over mutable subslices separated by elements that match `pred`. The matched element is contained in the previous subslice as a terminator.

# Examples

    let mut v = [10, 40, 30, 20, 60, 50];

    for group in v.split_inclusive_mut(|num| *num % 3 == 0) {
        let terminator_idx = group.len()-1;
        group[terminator_idx] = 1;
    }
    assert_eq!(v, [10, 40, 1, 20, 1, 1]);

#### `pub fn rsplit<F>(&self, pred: F) -> RSplit<'_, T, F> where
F: FnMut(&T) -> bool,` 1.27.0 [src]

Returns an iterator over subslices separated by elements that match `pred`, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

# Examples

    let slice = [11, 22, 33, 0, 44, 55];
    let mut iter = slice.rsplit(|num| *num == 0);

    assert_eq!(iter.next().unwrap(), &[44, 55]);
    assert_eq!(iter.next().unwrap(), &[11, 22, 33]);
    assert_eq!(iter.next(), None);

As with `split()`, if the first or last element is matched, an empty slice will be the first (or last) item returned by the iterator.

    let v = &[0, 1, 1, 2, 3, 5, 8];
    let mut it = v.rsplit(|n| *n % 2 == 0);
    assert_eq!(it.next().unwrap(), &[]);
    assert_eq!(it.next().unwrap(), &[3, 5]);
    assert_eq!(it.next().unwrap(), &[1, 1]);
    assert_eq!(it.next().unwrap(), &[]);
    assert_eq!(it.next(), None);

#### `pub fn rsplit_mut<F>(&mut self, pred: F) -> RSplitMut<'_, T, F> where
F: FnMut(&T) -> bool,` 1.27.0 [src]

Returns an iterator over mutable subslices separated by elements that match `pred`, starting at the end of the slice and working backwards. The matched element is not contained in the subslices.

# Examples

    let mut v = [100, 400, 300, 200, 600, 500];

    let mut count = 0;
    for group in v.rsplit_mut(|num| *num % 3 == 0) {
        count += 1;
        group[0] = count;
    }
    assert_eq!(v, [3, 400, 300, 2, 600, 1]);

#### `pub fn splitn<F>(&self, n: usize, pred: F) -> SplitN<'_, T, F> where
F: FnMut(&T) -> bool,` 1.0.0 [src]

Returns an iterator over subslices separated by elements that match `pred`, limited to returning at most `n` items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

# Examples

Print the slice split once by numbers divisible by 3 (i.e., `[10, 40]`, `[20, 60, 50]`):

    let v = [10, 40, 30, 20, 60, 50];

    for group in v.splitn(2, |num| *num % 3 == 0) {
        println!("{:?}", group);
    }

#### `pub fn splitn_mut<F>(&mut self, n: usize, pred: F) -> SplitNMut<'_, T, F> where
F: FnMut(&T) -> bool,` 1.0.0 [src]

Returns an iterator over subslices separated by elements that match `pred`, limited to returning at most `n` items. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

# Examples

    let mut v = [10, 40, 30, 20, 60, 50];

    for group in v.splitn_mut(2, |num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(v, [1, 40, 30, 1, 60, 50]);

#### `pub fn rsplitn<F>(&self, n: usize, pred: F) -> RSplitN<'_, T, F> where
F: FnMut(&T) -> bool,` 1.0.0 [src]

Returns an iterator over subslices separated by elements that match `pred` limited to returning at most `n` items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

# Examples

Print the slice split once, starting from the end, by numbers divisible by 3 (i.e., `[50]`, `[10, 40, 30, 20]`):

    let v = [10, 40, 30, 20, 60, 50];

    for group in v.rsplitn(2, |num| *num % 3 == 0) {
        println!("{:?}", group);
    }

#### `pub fn rsplitn_mut<F>(&mut self, n: usize, pred: F) -> RSplitNMut<'_, T, F> where
F: FnMut(&T) -> bool,` 1.0.0 [src]

Returns an iterator over subslices separated by elements that match `pred` limited to returning at most `n` items. This starts at the end of the slice and works backwards. The matched element is not contained in the subslices.

The last element returned, if any, will contain the remainder of the slice.

# Examples

    let mut s = [10, 40, 30, 20, 60, 50];

    for group in s.rsplitn_mut(2, |num| *num % 3 == 0) {
        group[0] = 1;
    }
    assert_eq!(s, [1, 40, 30, 20, 60, 1]);

#### `pub fn contains(&self, x: &T) -> bool where
T: PartialEq<T>,` 1.0.0 [src]

Returns `true` if the slice contains an element with the given value.

# Examples

    let v = [10, 40, 30];
    assert!(v.contains(&30));
    assert!(!v.contains(&50));

If you do not have an `&T`, but just an `&U` such that `T: Borrow<U>` (e.g. `String: Borrow<str>`), you can use `iter().any`:

    let v = [String::from("hello"), String::from("world")]; // slice of `String`
    assert!(v.iter().any(|e| e == "hello")); // search with `&str`
    assert!(!v.iter().any(|e| e == "hi"));

#### `pub fn starts_with(&self, needle: &[T]) -> bool where
T: PartialEq<T>,` 1.0.0 [src]

Returns `true` if `needle` is a prefix of the slice.

# Examples

    let v = [10, 40, 30];
    assert!(v.starts_with(&[10]));
    assert!(v.starts_with(&[10, 40]));
    assert!(!v.starts_with(&[50]));
    assert!(!v.starts_with(&[10, 50]));

Always returns `true` if `needle` is an empty slice:

    let v = &[10, 40, 30];
    assert!(v.starts_with(&[]));
    let v: &[u8] = &[];
    assert!(v.starts_with(&[]));

#### `pub fn ends_with(&self, needle: &[T]) -> bool where
T: PartialEq<T>,` 1.0.0 [src]

Returns `true` if `needle` is a suffix of the slice.

# Examples

    let v = [10, 40, 30];
    assert!(v.ends_with(&[30]));
    assert!(v.ends_with(&[40, 30]));
    assert!(!v.ends_with(&[50]));
    assert!(!v.ends_with(&[50, 30]));

Always returns `true` if `needle` is an empty slice:

    let v = &[10, 40, 30];
    assert!(v.ends_with(&[]));
    let v: &[u8] = &[];
    assert!(v.ends_with(&[]));

#### `#[must_use = "returns the subslice without modifying the original"]pub fn strip_prefix<P>(&self, prefix: &P) -> Option<&[T]> where
T: PartialEq<T>,
P: SlicePattern<Item = T> + ?Sized,` 1.51.0 [src]

Returns a subslice with the prefix removed.

If the slice starts with `prefix`, returns the subslice after the prefix, wrapped in `Some`. If `prefix` is empty, simply returns the original slice.

If the slice does not start with `prefix`, returns `None`.

# Examples

    let v = &[10, 40, 30];
    assert_eq!(v.strip_prefix(&[10]), Some(&[40, 30][..]));
    assert_eq!(v.strip_prefix(&[10, 40]), Some(&[30][..]));
    assert_eq!(v.strip_prefix(&[50]), None);
    assert_eq!(v.strip_prefix(&[10, 50]), None);

    let prefix : &str = "he";
    assert_eq!(b"hello".strip_prefix(prefix.as_bytes()),
               Some(b"llo".as_ref()));

#### `#[must_use = "returns the subslice without modifying the original"]pub fn strip_suffix<P>(&self, suffix: &P) -> Option<&[T]> where
T: PartialEq<T>,
P: SlicePattern<Item = T> + ?Sized,` 1.51.0 [src]

Returns a subslice with the suffix removed.

If the slice ends with `suffix`, returns the subslice before the suffix, wrapped in `Some`. If `suffix` is empty, simply returns the original slice.

If the slice does not end with `suffix`, returns `None`.

# Examples

    let v = &[10, 40, 30];
    assert_eq!(v.strip_suffix(&[30]), Some(&[10, 40][..]));
    assert_eq!(v.strip_suffix(&[40, 30]), Some(&[10][..]));
    assert_eq!(v.strip_suffix(&[50]), None);
    assert_eq!(v.strip_suffix(&[50, 30]), None);

#### `pub fn binary_search(&self, x: &T) -> Result<usize, usize> where
T: Ord,` 1.0.0 [src]

Binary searches this sorted slice for a given element.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also `binary_search_by`, `binary_search_by_key`, and `partition_point`.

# Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    assert_eq!(s.binary_search(&13),  Ok(9));
    assert_eq!(s.binary_search(&4),   Err(7));
    assert_eq!(s.binary_search(&100), Err(13));
    let r = s.binary_search(&1);
    assert!(match r { Ok(1..=4) => true, _ => false, });

If you want to insert an item to a sorted vector, while maintaining sort order:

    let mut s = vec![0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];
    let num = 42;
    let idx = s.binary_search(&num).unwrap_or_else(|x| x);
    s.insert(idx, num);
    assert_eq!(s, [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 42, 55]);

#### `pub fn binary_search_by<'a, F>(&'a self, f: F) -> Result<usize, usize> where
F: FnMut(&'a T) -> Ordering,` 1.0.0 [src]

Binary searches this sorted slice with a comparator function.

The comparator function should implement an order consistent with the sort order of the underlying slice, returning an order code that indicates whether its argument is `Less`, `Equal` or `Greater` the desired target.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also `binary_search`, `binary_search_by_key`, and `partition_point`.

# Examples

Looks up a series of four elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [0, 1, 1, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55];

    let seek = 13;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Ok(9));
    let seek = 4;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(7));
    let seek = 100;
    assert_eq!(s.binary_search_by(|probe| probe.cmp(&seek)), Err(13));
    let seek = 1;
    let r = s.binary_search_by(|probe| probe.cmp(&seek));
    assert!(match r { Ok(1..=4) => true, _ => false, });

#### `pub fn binary_search_by_key<'a, B, F>(
&'a self,
b: &B,
f: F
) -> Result<usize, usize> where
B: Ord,
F: FnMut(&'a T) -> B,` 1.10.0 [src]

Binary searches this sorted slice with a key extraction function.

Assumes that the slice is sorted by the key, for instance with `sort_by_key` using the same key extraction function.

If the value is found then `Result::Ok` is returned, containing the index of the matching element. If there are multiple matches, then any one of the matches could be returned. If the value is not found then `Result::Err` is returned, containing the index where a matching element could be inserted while maintaining sorted order.

See also `binary_search`, `binary_search_by`, and `partition_point`.

# Examples

Looks up a series of four elements in a slice of pairs sorted by their second elements. The first is found, with a uniquely determined position; the second and third are not found; the fourth could match any position in `[1, 4]`.

    let s = [(0, 0), (2, 1), (4, 1), (5, 1), (3, 1),
             (1, 2), (2, 3), (4, 5), (5, 8), (3, 13),
             (1, 21), (2, 34), (4, 55)];

    assert_eq!(s.binary_search_by_key(&13, |&(a, b)| b),  Ok(9));
    assert_eq!(s.binary_search_by_key(&4, |&(a, b)| b),   Err(7));
    assert_eq!(s.binary_search_by_key(&100, |&(a, b)| b), Err(13));
    let r = s.binary_search_by_key(&1, |&(a, b)| b);
    assert!(match r { Ok(1..=4) => true, _ => false, });

#### `pub fn sort_unstable(&mut self) where
T: Ord,` 1.20.0 [src]

Sorts the slice, but may not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

# Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice consists of several concatenated sorted sequences.

# Examples

    let mut v = [-5, 4, 1, -3, 2];

    v.sort_unstable();
    assert!(v == [-5, -3, 1, 2, 4]);

#### `pub fn sort_unstable_by<F>(&mut self, compare: F) where
F: FnMut(&T, &T) -> Ordering,` 1.20.0 [src]

Sorts the slice with a comparator function, but may not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(n * log(n)) worst-case.

The comparator function must define a total ordering for the elements in the slice. If the ordering is not total, the order of the elements is unspecified. An order is a total order if it is (for all `a`, `b` and `c`):

- total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and
- transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.

For example, while `f64` doesn’t implement `Ord` because `NaN != NaN`, we can use `partial_cmp` as our sort function when we know the slice doesn’t contain a `NaN`.

    let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
    floats.sort_unstable_by(|a, b| a.partial_cmp(b).unwrap());
    assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);

# Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

It is typically faster than stable sorting, except in a few special cases, e.g., when the slice consists of several concatenated sorted sequences.

# Examples

    let mut v = [5, 4, 1, 3, 2];
    v.sort_unstable_by(|a, b| a.cmp(b));
    assert!(v == [1, 2, 3, 4, 5]);

    // reverse sorting
    v.sort_unstable_by(|a, b| b.cmp(a));
    assert!(v == [5, 4, 3, 2, 1]);

#### `pub fn sort_unstable_by_key<K, F>(&mut self, f: F) where
F: FnMut(&T) -> K,
K: Ord,` 1.20.0 [src]

Sorts the slice with a key extraction function, but may not preserve the order of equal elements.

This sort is unstable (i.e., may reorder equal elements), in-place (i.e., does not allocate), and O(m * n * log(n)) worst-case, where the key function is O(m).

# Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

Due to its key calling strategy, `sort_unstable_by_key` is likely to be slower than `sort_by_cached_key` in cases where the key function is expensive.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    v.sort_unstable_by_key(|k| k.abs());
    assert!(v == [1, 2, -3, 4, -5]);

#### `pub fn partition_at_index(
&mut self,
index: usize
) -> (&mut [T], &mut T, &mut [T]) where
T: Ord,` [src]

👎 Deprecated since 1.49.0:

use the select_nth_unstable() instead

🔬 This is a nightly-only experimental API. (`slice_partition_at_index`)

Reorder the slice such that the element at `index` is at its final sorted position.

#### `pub fn partition_at_index_by<F>(
&mut self,
index: usize,
compare: F
) -> (&mut [T], &mut T, &mut [T]) where
F: FnMut(&T, &T) -> Ordering,` [src]

👎 Deprecated since 1.49.0:

use select_nth_unstable_by() instead

🔬 This is a nightly-only experimental API. (`slice_partition_at_index`)

Reorder the slice with a comparator function such that the element at `index` is at its final sorted position.

#### `pub fn partition_at_index_by_key<K, F>(
&mut self,
index: usize,
f: F
) -> (&mut [T], &mut T, &mut [T]) where
F: FnMut(&T) -> K,
K: Ord,` [src]

👎 Deprecated since 1.49.0:

use the select_nth_unstable_by_key() instead

🔬 This is a nightly-only experimental API. (`slice_partition_at_index`)

Reorder the slice with a key extraction function such that the element at `index` is at its final sorted position.

#### `pub fn select_nth_unstable(
&mut self,
index: usize
) -> (&mut [T], &mut T, &mut [T]) where
T: Ord,` 1.49.0 [src]

Reorder the slice such that the element at `index` is at its final sorted position.

This reordering has the additional property that any value at position `i < index` will be less than or equal to any value at a position `j > index`. Additionally, this reordering is unstable (i.e. any number of equal elements may end up at position `index`), in-place (i.e. does not allocate), and O(n) worst-case. This function is also/ known as “kth element” in other libraries. It returns a triplet of the following values: all elements less than the one at the given index, the value at the given index, and all elements greater than the one at the given index.

# Current implementation

The current algorithm is based on the quickselect portion of the same quicksort algorithm used for `sort_unstable`.

# Panics

Panics when `index >= len()`, meaning it always panics on empty slices.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    // Find the median
    v.select_nth_unstable(2);

    // We are only guaranteed the slice will be one of the following, based on the way we sort
    // about the specified index.
    assert!(v == [-3, -5, 1, 2, 4] ||
            v == [-5, -3, 1, 2, 4] ||
            v == [-3, -5, 1, 4, 2] ||
            v == [-5, -3, 1, 4, 2]);

#### `pub fn select_nth_unstable_by<F>(
&mut self,
index: usize,
compare: F
) -> (&mut [T], &mut T, &mut [T]) where
F: FnMut(&T, &T) -> Ordering,` 1.49.0 [src]

Reorder the slice with a comparator function such that the element at `index` is at its final sorted position.

This reordering has the additional property that any value at position `i < index` will be less than or equal to any value at a position `j > index` using the comparator function. Additionally, this reordering is unstable (i.e. any number of equal elements may end up at position `index`), in-place (i.e. does not allocate), and O(n) worst-case. This function is also known as “kth element” in other libraries. It returns a triplet of the following values: all elements less than the one at the given index, the value at the given index, and all elements greater than the one at the given index, using the provided comparator function.

# Current implementation

The current algorithm is based on the quickselect portion of the same quicksort algorithm used for `sort_unstable`.

# Panics

Panics when `index >= len()`, meaning it always panics on empty slices.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    // Find the median as if the slice were sorted in descending order.
    v.select_nth_unstable_by(2, |a, b| b.cmp(a));

    // We are only guaranteed the slice will be one of the following, based on the way we sort
    // about the specified index.
    assert!(v == [2, 4, 1, -5, -3] ||
            v == [2, 4, 1, -3, -5] ||
            v == [4, 2, 1, -5, -3] ||
            v == [4, 2, 1, -3, -5]);

#### `pub fn select_nth_unstable_by_key<K, F>(
&mut self,
index: usize,
f: F
) -> (&mut [T], &mut T, &mut [T]) where
F: FnMut(&T) -> K,
K: Ord,` 1.49.0 [src]

Reorder the slice with a key extraction function such that the element at `index` is at its final sorted position.

This reordering has the additional property that any value at position `i < index` will be less than or equal to any value at a position `j > index` using the key extraction function. Additionally, this reordering is unstable (i.e. any number of equal elements may end up at position `index`), in-place (i.e. does not allocate), and O(n) worst-case. This function is also known as “kth element” in other libraries. It returns a triplet of the following values: all elements less than the one at the given index, the value at the given index, and all elements greater than the one at the given index, using the provided key extraction function.

# Current implementation

The current algorithm is based on the quickselect portion of the same quicksort algorithm used for `sort_unstable`.

# Panics

Panics when `index >= len()`, meaning it always panics on empty slices.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    // Return the median as if the array were sorted according to absolute value.
    v.select_nth_unstable_by_key(2, |a| a.abs());

    // We are only guaranteed the slice will be one of the following, based on the way we sort
    // about the specified index.
    assert!(v == [1, 2, -3, 4, -5] ||
            v == [1, 2, -3, -5, 4] ||
            v == [2, 1, -3, 4, -5] ||
            v == [2, 1, -3, -5, 4]);

#### `pub fn partition_dedup(&mut self) -> (&mut [T], &mut [T]) where
T: PartialEq<T>,` [src]

🔬 This is a nightly-only experimental API. (`slice_partition_dedup`)

Moves all consecutive repeated elements to the end of the slice according to the `PartialEq` trait implementation.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

If the slice is sorted, the first returned slice contains no duplicates.

# Examples

    #![feature(slice_partition_dedup)]

    let mut slice = [1, 2, 2, 3, 3, 2, 1, 1];

    let (dedup, duplicates) = slice.partition_dedup();

    assert_eq!(dedup, [1, 2, 3, 2, 1]);
    assert_eq!(duplicates, [2, 3, 1]);

#### `pub fn partition_dedup_by<F>(&mut self, same_bucket: F) -> (&mut [T], &mut [T]) where
F: FnMut(&mut T, &mut T) -> bool,` [src]

🔬 This is a nightly-only experimental API. (`slice_partition_dedup`)

Moves all but the first of consecutive elements to the end of the slice satisfying a given equality relation.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

The `same_bucket` function is passed references to two elements from the slice and must determine if the elements compare equal. The elements are passed in opposite order from their order in the slice, so if `same_bucket(a, b)` returns `true`, `a` is moved at the end of the slice.

If the slice is sorted, the first returned slice contains no duplicates.

# Examples

    #![feature(slice_partition_dedup)]

    let mut slice = ["foo", "Foo", "BAZ", "Bar", "bar", "baz", "BAZ"];

    let (dedup, duplicates) = slice.partition_dedup_by(|a, b| a.eq_ignore_ascii_case(b));

    assert_eq!(dedup, ["foo", "BAZ", "Bar", "baz"]);
    assert_eq!(duplicates, ["bar", "Foo", "BAZ"]);

#### `pub fn partition_dedup_by_key<K, F>(&mut self, key: F) -> (&mut [T], &mut [T]) where
F: FnMut(&mut T) -> K,
K: PartialEq<K>,` [src]

🔬 This is a nightly-only experimental API. (`slice_partition_dedup`)

Moves all but the first of consecutive elements to the end of the slice that resolve to the same key.

Returns two slices. The first contains no consecutive repeated elements. The second contains all the duplicates in no specified order.

If the slice is sorted, the first returned slice contains no duplicates.

# Examples

    #![feature(slice_partition_dedup)]

    let mut slice = [10, 20, 21, 30, 30, 20, 11, 13];

    let (dedup, duplicates) = slice.partition_dedup_by_key(|i| *i / 10);

    assert_eq!(dedup, [10, 20, 30, 20, 11]);
    assert_eq!(duplicates, [21, 30, 13]);

#### `pub fn rotate_left(&mut self, mid: usize)`1.26.0 [src]

Rotates the slice in-place such that the first `mid` elements of the slice move to the end while the last `self.len() - mid` elements move to the front. After calling `rotate_left`, the element previously at index `mid` will become the first element in the slice.

# Panics

This function will panic if `mid` is greater than the length of the slice. Note that `mid == self.len()` does not panic and is a no-op rotation.

# Complexity

Takes linear (in `self.len()`) time.

# Examples

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a.rotate_left(2);
    assert_eq!(a, ['c', 'd', 'e', 'f', 'a', 'b']);

Rotating a subslice:

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a[1..5].rotate_left(1);
    assert_eq!(a, ['a', 'c', 'd', 'e', 'b', 'f']);

#### `pub fn rotate_right(&mut self, k: usize)`1.26.0 [src]

Rotates the slice in-place such that the first `self.len() - k` elements of the slice move to the end while the last `k` elements move to the front. After calling `rotate_right`, the element previously at index `self.len() - k` will become the first element in the slice.

# Panics

This function will panic if `k` is greater than the length of the slice. Note that `k == self.len()` does not panic and is a no-op rotation.

# Complexity

Takes linear (in `self.len()`) time.

# Examples

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a.rotate_right(2);
    assert_eq!(a, ['e', 'f', 'a', 'b', 'c', 'd']);

Rotate a subslice:

    let mut a = ['a', 'b', 'c', 'd', 'e', 'f'];
    a[1..5].rotate_right(1);
    assert_eq!(a, ['a', 'e', 'b', 'c', 'd', 'f']);

#### `pub fn fill(&mut self, value: T) where
T: Clone,` 1.50.0 [src]

Fills `self` with elements by cloning `value`.

# Examples

    let mut buf = vec![0; 10];
    buf.fill(1);
    assert_eq!(buf, vec![1; 10]);

#### `pub fn fill_with<F>(&mut self, f: F) where
F: FnMut() -> T,` 1.51.0 [src]

Fills `self` with elements returned by calling a closure repeatedly.

This method uses a closure to create new values. If you’d rather `Clone` a given value, use `fill`. If you want to use the `Default` trait to generate values, you can pass `Default::default` as the argument.

# Examples

    let mut buf = vec![1; 10];
    buf.fill_with(Default::default);
    assert_eq!(buf, vec![0; 10]);

#### `pub fn clone_from_slice(&mut self, src: &[T]) where
T: Clone,` 1.7.0 [src]

Copies the elements from `src` into `self`.

The length of `src` must be the same as `self`.

If `T` implements `Copy`, it can be more performant to use `copy_from_slice`.

# Panics

This function will panic if the two slices have different lengths.

# Examples

Cloning two elements from a slice into another:

    let src = [1, 2, 3, 4];
    let mut dst = [0, 0];

    // Because the slices have to be the same length,
    // we slice the source slice from four elements
    // to two. It will panic if we don't do this.
    dst.clone_from_slice(&src[2..]);

    assert_eq!(src, [1, 2, 3, 4]);
    assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use `clone_from_slice` on a single slice will result in a compile failure:

ⓘ

    let mut slice = [1, 2, 3, 4, 5];

    slice[..2].clone_from_slice(&slice[3..]); // compile fail!

To work around this, we can use `split_at_mut` to create two distinct sub-slices from a slice:

    let mut slice = [1, 2, 3, 4, 5];

    {
        let (left, right) = slice.split_at_mut(2);
        left.clone_from_slice(&right[1..]);
    }

    assert_eq!(slice, [4, 5, 3, 4, 5]);

#### `pub fn copy_from_slice(&mut self, src: &[T]) where
T: Copy,` 1.9.0 [src]

Copies all elements from `src` into `self`, using a memcpy.

The length of `src` must be the same as `self`.

If `T` does not implement `Copy`, use `clone_from_slice`.

# Panics

This function will panic if the two slices have different lengths.

# Examples

Copying two elements from a slice into another:

    let src = [1, 2, 3, 4];
    let mut dst = [0, 0];

    // Because the slices have to be the same length,
    // we slice the source slice from four elements
    // to two. It will panic if we don't do this.
    dst.copy_from_slice(&src[2..]);

    assert_eq!(src, [1, 2, 3, 4]);
    assert_eq!(dst, [3, 4]);

Rust enforces that there can only be one mutable reference with no immutable references to a particular piece of data in a particular scope. Because of this, attempting to use `copy_from_slice` on a single slice will result in a compile failure:

ⓘ

    let mut slice = [1, 2, 3, 4, 5];

    slice[..2].copy_from_slice(&slice[3..]); // compile fail!

To work around this, we can use `split_at_mut` to create two distinct sub-slices from a slice:

    let mut slice = [1, 2, 3, 4, 5];

    {
        let (left, right) = slice.split_at_mut(2);
        left.copy_from_slice(&right[1..]);
    }

    assert_eq!(slice, [4, 5, 3, 4, 5]);

#### `pub fn copy_within<R>(&mut self, src: R, dest: usize) where
T: Copy,
R: RangeBounds<usize>,` 1.37.0 [src]

Copies elements from one part of the slice to another part of itself, using a memmove.

`src` is the range within `self` to copy from. `dest` is the starting index of the range within `self` to copy to, which will have the same length as `src`. The two ranges may overlap. The ends of the two ranges must be less than or equal to `self.len()`.

# Panics

This function will panic if either range exceeds the end of the slice, or if the end of `src` is before the start.

# Examples

Copying four bytes within a slice:

    let mut bytes = *b"Hello, World!";

    bytes.copy_within(1..5, 8);

    assert_eq!(&bytes, b"Hello, Wello!");

#### `pub fn swap_with_slice(&mut self, other: &mut [T])`1.27.0 [src]

Swaps all elements in `self` with those in `other`.

The length of `other` must be the same as `self`.

# Panics

This function will panic if the two slices have different lengths.

# Example

Swapping two elements across slices:

    let mut slice1 = [0, 0];
    let mut slice2 = [1, 2, 3, 4];

    slice1.swap_with_slice(&mut slice2[2..]);

    assert_eq!(slice1, [3, 4]);
    assert_eq!(slice2, [1, 2, 0, 0]);

Rust enforces that there can only be one mutable reference to a particular piece of data in a particular scope. Because of this, attempting to use `swap_with_slice` on a single slice will result in a compile failure:

ⓘ

    let mut slice = [1, 2, 3, 4, 5];
    slice[..2].swap_with_slice(&mut slice[3..]); // compile fail!

To work around this, we can use `split_at_mut` to create two distinct mutable sub-slices from a slice:

    let mut slice = [1, 2, 3, 4, 5];

    {
        let (left, right) = slice.split_at_mut(2);
        left.swap_with_slice(&mut right[1..]);
    }

    assert_eq!(slice, [4, 5, 3, 1, 2]);

#### `pub unsafe fn align_to<U>(&self) -> (&[T], &[U], &[T])`1.30.0 [src]

Transmute the slice to a slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The method may make the middle slice the greatest length possible for a given type and input slice, but only your algorithm’s performance should depend on that, not its correctness. It is permissible for all of the input data to be returned as the prefix or suffix slice.

This method has no purpose when either input element `T` or output element `U` are zero-sized and will return the original slice without splitting anything.

# Safety

This method is essentially a `transmute` with respect to the elements in the returned middle slice, so all the usual caveats pertaining to `transmute::<T, U>` also apply here.

# Examples

Basic usage:

    unsafe {
        let bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
        let (prefix, shorts, suffix) = bytes.align_to::<u16>();
        // less_efficient_algorithm_for_bytes(prefix);
        // more_efficient_algorithm_for_aligned_shorts(shorts);
        // less_efficient_algorithm_for_bytes(suffix);
    }

#### `pub unsafe fn align_to_mut<U>(&mut self) -> (&mut [T], &mut [U], &mut [T])`1.30.0 [src]

Transmute the slice to a slice of another type, ensuring alignment of the types is maintained.

This method splits the slice into three distinct slices: prefix, correctly aligned middle slice of a new type, and the suffix slice. The method may make the middle slice the greatest length possible for a given type and input slice, but only your algorithm’s performance should depend on that, not its correctness. It is permissible for all of the input data to be returned as the prefix or suffix slice.

This method has no purpose when either input element `T` or output element `U` are zero-sized and will return the original slice without splitting anything.

# Safety

This method is essentially a `transmute` with respect to the elements in the returned middle slice, so all the usual caveats pertaining to `transmute::<T, U>` also apply here.

# Examples

Basic usage:

    unsafe {
        let mut bytes: [u8; 7] = [1, 2, 3, 4, 5, 6, 7];
        let (prefix, shorts, suffix) = bytes.align_to_mut::<u16>();
        // less_efficient_algorithm_for_bytes(prefix);
        // more_efficient_algorithm_for_aligned_shorts(shorts);
        // less_efficient_algorithm_for_bytes(suffix);
    }

#### `pub fn is_sorted(&self) -> bool where
T: PartialOrd<T>,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted`)

new API

Checks if the elements of this slice are sorted.

That is, for each element `a` and its following element `b`, `a <= b` must hold. If the slice yields exactly zero or one element, `true` is returned.

Note that if `Self::Item` is only `PartialOrd`, but not `Ord`, the above definition implies that this function returns `false` if any two consecutive items are not comparable.

# Examples

    #![feature(is_sorted)]
    let empty: [i32; 0] = [];

    assert!([1, 2, 2, 9].is_sorted());
    assert!(![1, 3, 2, 4].is_sorted());
    assert!([0].is_sorted());
    assert!(empty.is_sorted());
    assert!(![0.0, 1.0, f32::NAN].is_sorted());

#### `pub fn is_sorted_by<F>(&self, compare: F) -> bool where
F: FnMut(&T, &T) -> Option<Ordering>,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted`)

new API

Checks if the elements of this slice are sorted using the given comparator function.

Instead of using `PartialOrd::partial_cmp`, this function uses the given `compare` function to determine the ordering of two elements. Apart from that, it’s equivalent to `is_sorted`; see its documentation for more information.

#### `pub fn is_sorted_by_key<F, K>(&self, f: F) -> bool where
F: FnMut(&T) -> K,
K: PartialOrd<K>,` [src]

🔬 This is a nightly-only experimental API. (`is_sorted`)

new API

Checks if the elements of this slice are sorted using the given key extraction function.

Instead of comparing the slice’s elements directly, this function compares the keys of the elements, as determined by `f`. Apart from that, it’s equivalent to `is_sorted`; see its documentation for more information.

# Examples

    #![feature(is_sorted)]

    assert!(["c", "bb", "aaa"].is_sorted_by_key(|s| s.len()));
    assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));

#### `pub fn partition_point<P>(&self, pred: P) -> usize where
P: FnMut(&T) -> bool,` 1.52.0 [src]

Returns the index of the partition point according to the given predicate (the index of the first element of the second partition).

The slice is assumed to be partitioned according to the given predicate. This means that all elements for which the predicate returns true are at the start of the slice and all elements for which the predicate returns false are at the end. For example, [7, 15, 3, 5, 4, 12, 6] is a partitioned under the predicate x % 2 != 0 (all odd numbers are at the start, all even at the end).

If this slice is not partitioned, the returned result is unspecified and meaningless, as this method performs a kind of binary search.

See also `binary_search`, `binary_search_by`, and `binary_search_by_key`.

# Examples

    let v = [1, 2, 3, 3, 5, 6, 7];
    let i = v.partition_point(|&x| x < 5);

    assert_eq!(i, 4);
    assert!(v[..i].iter().all(|&x| x < 5));
    assert!(v[i..].iter().all(|&x| !(x < 5)));

#### `pub fn is_ascii(&self) -> bool` 1.23.0 [src]

Checks if all bytes in this slice are within the ASCII range.

#### `pub fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool` 1.23.0 [src]

Checks that two slices are an ASCII case-insensitive match.

Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`, but without allocating and copying temporaries.

#### `pub fn make_ascii_uppercase(&mut self)`1.23.0 [src]

Converts this slice to its ASCII upper case equivalent in-place.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To return a new uppercased value without modifying the existing one, use `to_ascii_uppercase`.

#### `pub fn make_ascii_lowercase(&mut self)`1.23.0 [src]

Converts this slice to its ASCII lower case equivalent in-place.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To return a new lowercased value without modifying the existing one, use `to_ascii_lowercase`.

#### `pub fn sort(&mut self) where
T: Ord,` 1.0.0 [src]

Sorts the slice.

This sort is stable (i.e., does not reorder equal elements) and O(n * log(n)) worst-case.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See `sort_unstable`.

# Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of `self`, but for short slices a non-allocating insertion sort is used instead.

# Examples

    let mut v = [-5, 4, 1, -3, 2];

    v.sort();
    assert!(v == [-5, -3, 1, 2, 4]);

#### `pub fn sort_by<F>(&mut self, compare: F) where
F: FnMut(&T, &T) -> Ordering,` 1.0.0 [src]

Sorts the slice with a comparator function.

This sort is stable (i.e., does not reorder equal elements) and O(n * log(n)) worst-case.

The comparator function must define a total ordering for the elements in the slice. If the ordering is not total, the order of the elements is unspecified. An order is a total order if it is (for all `a`, `b` and `c`):

- total and antisymmetric: exactly one of `a < b`, `a == b` or `a > b` is true, and
- transitive, `a < b` and `b < c` implies `a < c`. The same must hold for both `==` and `>`.

For example, while `f64` doesn’t implement `Ord` because `NaN != NaN`, we can use `partial_cmp` as our sort function when we know the slice doesn’t contain a `NaN`.

    let mut floats = [5f64, 4.0, 1.0, 3.0, 2.0];
    floats.sort_by(|a, b| a.partial_cmp(b).unwrap());
    assert_eq!(floats, [1.0, 2.0, 3.0, 4.0, 5.0]);

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See `sort_unstable_by`.

# Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of `self`, but for short slices a non-allocating insertion sort is used instead.

# Examples

    let mut v = [5, 4, 1, 3, 2];
    v.sort_by(|a, b| a.cmp(b));
    assert!(v == [1, 2, 3, 4, 5]);

    // reverse sorting
    v.sort_by(|a, b| b.cmp(a));
    assert!(v == [5, 4, 3, 2, 1]);

#### `pub fn sort_by_key<K, F>(&mut self, f: F) where
F: FnMut(&T) -> K,
K: Ord,` 1.7.0 [src]

Sorts the slice with a key extraction function.

This sort is stable (i.e., does not reorder equal elements) and O(m * n * log(n)) worst-case, where the key function is O(m).

For expensive key functions (e.g. functions that are not simple property accesses or basic operations), `sort_by_cached_key` is likely to be significantly faster, as it does not recompute element keys.

When applicable, unstable sorting is preferred because it is generally faster than stable sorting and it doesn’t allocate auxiliary memory. See `sort_unstable_by_key`.

# Current implementation

The current algorithm is an adaptive, iterative merge sort inspired by timsort. It is designed to be very fast in cases where the slice is nearly sorted, or consists of two or more sorted sequences concatenated one after another.

Also, it allocates temporary storage half the size of `self`, but for short slices a non-allocating insertion sort is used instead.

# Examples

    let mut v = [-5i32, 4, 1, -3, 2];

    v.sort_by_key(|k| k.abs());
    assert!(v == [1, 2, -3, 4, -5]);

#### `pub fn sort_by_cached_key<K, F>(&mut self, f: F) where
F: FnMut(&T) -> K,
K: Ord,` 1.34.0 [src]

Sorts the slice with a key extraction function.

During sorting, the key function is called only once per element.

This sort is stable (i.e., does not reorder equal elements) and O(m * n + n * log(n)) worst-case, where the key function is O(m).

For simple key functions (e.g., functions that are property accesses or basic operations), `sort_by_key` is likely to be faster.

# Current implementation

The current algorithm is based on pattern-defeating quicksort by Orson Peters, which combines the fast average case of randomized quicksort with the fast worst case of heapsort, while achieving linear time on slices with certain patterns. It uses some randomization to avoid degenerate cases, but with a fixed seed to always provide deterministic behavior.

In the worst case, the algorithm allocates temporary storage in a `Vec<(K, usize)>` the length of the slice.

# Examples

    let mut v = [-5i32, 4, 32, -3, 2];

    v.sort_by_cached_key(|k| k.to_string());
    assert!(v == [-3, -5, 2, 32, 4]);

#### `pub fn to_vec(&self) -> Vec<T, Global> where
T: Clone,` 1.0.0 [src]

Copies `self` into a new `Vec`.

# Examples

    let s = [10, 40, 30];
    let x = s.to_vec();
    // Here, `s` and `x` can be modified independently.

#### `pub fn to_vec_in<A>(&self, alloc: A) -> Vec<T, A> where
T: Clone,
A: Allocator,` [src]

🔬 This is a nightly-only experimental API. (`allocator_api`)

Copies `self` into a new `Vec` with an allocator.

# Examples

    #![feature(allocator_api)]

    use std::alloc::System;

    let s = [10, 40, 30];
    let x = s.to_vec_in(System);
    // Here, `s` and `x` can be modified independently.

#### `pub fn repeat(&self, n: usize) -> Vec<T, Global> where
T: Copy,` 1.40.0 [src]

Creates a vector by repeating a slice `n` times.

# Panics

This function will panic if the capacity would overflow.

# Examples

Basic usage:

    assert_eq!([1, 2].repeat(3), vec![1, 2, 1, 2, 1, 2]);

A panic upon overflow:

ⓘ

    // this will panic at runtime
    b"0123456789abcdef".repeat(usize::MAX);

#### `pub fn concat<Item>(&self) -> <[T] as Concat<Item>>::Outputⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
where
Item: ?Sized,
[T]: Concat<Item>,` 1.0.0 [src]

Flattens a slice of `T` into a single value `Self::Output`.

# Examples

    assert_eq!(["hello", "world"].concat(), "helloworld");
    assert_eq!([[1, 2], [3, 4]].concat(), [1, 2, 3, 4]);

#### `pub fn join<Separator>(
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
where
[T]: Join<Separator>,` 1.3.0 [src]

Flattens a slice of `T` into a single value `Self::Output`, placing a given separator between each.

# Examples

    assert_eq!(["hello", "world"].join(" "), "hello world");
    assert_eq!([[1, 2], [3, 4]].join(&0), [1, 2, 0, 3, 4]);
    assert_eq!([[1, 2], [3, 4]].join(&[0, 0][..]), [1, 2, 0, 0, 3, 4]);

#### `pub fn connect<Separator>(
&self,
sep: Separator
) -> <[T] as Join<Separator>>::Outputⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
where
[T]: Join<Separator>,` 1.0.0 [src]

👎 Deprecated since 1.3.0:

renamed to join

Flattens a slice of `T` into a single value `Self::Output`, placing a given separator between each.

# Examples

    assert_eq!(["hello", "world"].connect(" "), "hello world");
    assert_eq!([[1, 2], [3, 4]].connect(&0), [1, 2, 0, 3, 4]);

#### `pub fn to_ascii_uppercase(&self) -> Vec<u8, Global>`1.23.0 [src]

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII upper case equivalent.

ASCII letters ‘a’ to ‘z’ are mapped to ‘A’ to ‘Z’, but non-ASCII letters are unchanged.

To uppercase the value in-place, use `make_ascii_uppercase`.

#### `pub fn to_ascii_lowercase(&self) -> Vec<u8, Global>`1.23.0 [src]

Returns a vector containing a copy of this slice where each byte is mapped to its ASCII lower case equivalent.

ASCII letters ‘A’ to ‘Z’ are mapped to ‘a’ to ‘z’, but non-ASCII letters are unchanged.

To lowercase the value in-place, use `make_ascii_lowercase`.

## Trait Implementations

### `impl AsMut<[u8]> for BytesMut` [src]

#### `fn as_mut(&mut self) -> &mut [u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Performs the conversion.

### `impl AsRef<[u8]> for BytesMut` [src]

#### `fn as_ref(&self) -> &[u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Performs the conversion.

### `impl Borrow<[u8]> for BytesMut` [src]

#### `fn borrow(&self) -> &[u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Immutably borrows from an owned value. Read more

### `impl BorrowMut<[u8]> for BytesMut` [src]

#### `fn borrow_mut(&mut self) -> &mut [u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Mutably borrows from an owned value. Read more

### `impl Buf for BytesMut` [src]

#### `fn remaining(&self) -> usize` [src]

Returns the number of bytes between the current position and the end of the buffer. Read more

#### `fn chunk(&self) -> &[u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Returns a slice starting at the current position and of length between 0 and `Buf::remaining()`. Note that this can return shorter slice (this allows non-continuous internal representation). Read more

#### `fn advance(&mut self, cnt: usize)` [src]

Advance the internal cursor of the Buf Read more

#### `fn copy_to_bytes(&mut self, len: usize) -> Bytes` [src]

Consumes `len` bytes inside self and returns new instance of `Bytes` with this data. Read more

#### `fn chunks_vectored<'a>(&'a self, dst: &mut [IoSlice<'a>]) -> usize` [src]

Fills `dst` with potentially multiple slices starting at `self`’s current position. Read more

#### `fn has_remaining(&self) -> bool` [src]

Returns true if there are any more bytes to consume Read more

#### `fn copy_to_slice(&mut self, dst: &mut [u8])` [src]

Copies bytes from `self` into `dst`. Read more

#### `fn get_u8(&mut self) -> u8` [src]

Gets an unsigned 8 bit integer from `self`. Read more

#### `fn get_i8(&mut self) -> i8` [src]

Gets a signed 8 bit integer from `self`. Read more

#### `fn get_u16(&mut self) -> u16` [src]

Gets an unsigned 16 bit integer from `self` in big-endian byte order. Read more

#### `fn get_u16_le(&mut self) -> u16` [src]

Gets an unsigned 16 bit integer from `self` in little-endian byte order. Read more

#### `fn get_i16(&mut self) -> i16` [src]

Gets a signed 16 bit integer from `self` in big-endian byte order. Read more

#### `fn get_i16_le(&mut self) -> i16` [src]

Gets a signed 16 bit integer from `self` in little-endian byte order. Read more

#### `fn get_u32(&mut self) -> u32` [src]

Gets an unsigned 32 bit integer from `self` in the big-endian byte order. Read more

#### `fn get_u32_le(&mut self) -> u32` [src]

Gets an unsigned 32 bit integer from `self` in the little-endian byte order. Read more

#### `fn get_i32(&mut self) -> i32` [src]

Gets a signed 32 bit integer from `self` in big-endian byte order. Read more

#### `fn get_i32_le(&mut self) -> i32` [src]

Gets a signed 32 bit integer from `self` in little-endian byte order. Read more

#### `fn get_u64(&mut self) -> u64` [src]

Gets an unsigned 64 bit integer from `self` in big-endian byte order. Read more

#### `fn get_u64_le(&mut self) -> u64` [src]

Gets an unsigned 64 bit integer from `self` in little-endian byte order. Read more

#### `fn get_i64(&mut self) -> i64` [src]

Gets a signed 64 bit integer from `self` in big-endian byte order. Read more

#### `fn get_i64_le(&mut self) -> i64` [src]

Gets a signed 64 bit integer from `self` in little-endian byte order. Read more

#### `fn get_u128(&mut self) -> u128` [src]

Gets an unsigned 128 bit integer from `self` in big-endian byte order. Read more

#### `fn get_u128_le(&mut self) -> u128` [src]

Gets an unsigned 128 bit integer from `self` in little-endian byte order. Read more

#### `fn get_i128(&mut self) -> i128` [src]

Gets a signed 128 bit integer from `self` in big-endian byte order. Read more

#### `fn get_i128_le(&mut self) -> i128` [src]

Gets a signed 128 bit integer from `self` in little-endian byte order. Read more

#### `fn get_uint(&mut self, nbytes: usize) -> u64` [src]

Gets an unsigned n-byte integer from `self` in big-endian byte order. Read more

#### `fn get_uint_le(&mut self, nbytes: usize) -> u64` [src]

Gets an unsigned n-byte integer from `self` in little-endian byte order. Read more

#### `fn get_int(&mut self, nbytes: usize) -> i64` [src]

Gets a signed n-byte integer from `self` in big-endian byte order. Read more

#### `fn get_int_le(&mut self, nbytes: usize) -> i64` [src]

Gets a signed n-byte integer from `self` in little-endian byte order. Read more

#### `fn get_f32(&mut self) -> f32` [src]

Gets an IEEE754 single-precision (4 bytes) floating point number from `self` in big-endian byte order. Read more

#### `fn get_f32_le(&mut self) -> f32` [src]

Gets an IEEE754 single-precision (4 bytes) floating point number from `self` in little-endian byte order. Read more

#### `fn get_f64(&mut self) -> f64` [src]

Gets an IEEE754 double-precision (8 bytes) floating point number from `self` in big-endian byte order. Read more

#### `fn get_f64_le(&mut self) -> f64` [src]

Gets an IEEE754 double-precision (8 bytes) floating point number from `self` in little-endian byte order. Read more

#### `fn take(self, limit: usize) -> Take<Self> where
Self: Sized,` [src]

Creates an adaptor which will read at most `limit` bytes from `self`. Read more

#### `fn chain<U: Buf>(self, next: U) -> Chain<Self, U> where
Self: Sized,` [src]

Creates an adaptor which will chain this buffer with another. Read more

#### `fn reader(self) -> Reader<Self>ⓘ

### Notable traits for Reader<B>

`impl<B: Buf + Sized> Read for Reader<B>`
where
Self: Sized,` [src]

Creates an adaptor which implements the `Read` trait for `self`. Read more

### `impl BufMut for BytesMut` [src]

#### `fn remaining_mut(&self) -> usize` [src]

Returns the number of bytes that can be written from the current position until the end of the buffer is reached. Read more

#### `unsafe fn advance_mut(&mut self, cnt: usize)` [src]

Advance the internal cursor of the BufMut Read more

#### `fn chunk_mut(&mut self) -> &mut UninitSlice` [src]

Returns a mutable slice starting at the current BufMut position and of length between 0 and `BufMut::remaining_mut()`. Note that this can be shorter than the whole remainder of the buffer (this allows non-continuous implementation). Read more

#### `fn put<T: Buf>(&mut self, src: T) where
Self: Sized,` [src]

Transfer bytes into `self` from `src` and advance the cursor by the number of bytes written. Read more

#### `fn put_slice(&mut self, src: &[u8])` [src]

Transfer bytes into `self` from `src` and advance the cursor by the number of bytes written. Read more

#### `fn has_remaining_mut(&self) -> bool` [src]

Returns true if there is space in `self` for more bytes. Read more

#### `fn put_u8(&mut self, n: u8)` [src]

Writes an unsigned 8 bit integer to `self`. Read more

#### `fn put_i8(&mut self, n: i8)` [src]

Writes a signed 8 bit integer to `self`. Read more

#### `fn put_u16(&mut self, n: u16)` [src]

Writes an unsigned 16 bit integer to `self` in big-endian byte order. Read more

#### `fn put_u16_le(&mut self, n: u16)` [src]

Writes an unsigned 16 bit integer to `self` in little-endian byte order. Read more

#### `fn put_i16(&mut self, n: i16)` [src]

Writes a signed 16 bit integer to `self` in big-endian byte order. Read more

#### `fn put_i16_le(&mut self, n: i16)` [src]

Writes a signed 16 bit integer to `self` in little-endian byte order. Read more

#### `fn put_u32(&mut self, n: u32)` [src]

Writes an unsigned 32 bit integer to `self` in big-endian byte order. Read more

#### `fn put_u32_le(&mut self, n: u32)` [src]

Writes an unsigned 32 bit integer to `self` in little-endian byte order. Read more

#### `fn put_i32(&mut self, n: i32)` [src]

Writes a signed 32 bit integer to `self` in big-endian byte order. Read more

#### `fn put_i32_le(&mut self, n: i32)` [src]

Writes a signed 32 bit integer to `self` in little-endian byte order. Read more

#### `fn put_u64(&mut self, n: u64)` [src]

Writes an unsigned 64 bit integer to `self` in the big-endian byte order. Read more

#### `fn put_u64_le(&mut self, n: u64)` [src]

Writes an unsigned 64 bit integer to `self` in little-endian byte order. Read more

#### `fn put_i64(&mut self, n: i64)` [src]

Writes a signed 64 bit integer to `self` in the big-endian byte order. Read more

#### `fn put_i64_le(&mut self, n: i64)` [src]

Writes a signed 64 bit integer to `self` in little-endian byte order. Read more

#### `fn put_u128(&mut self, n: u128)` [src]

Writes an unsigned 128 bit integer to `self` in the big-endian byte order. Read more

#### `fn put_u128_le(&mut self, n: u128)` [src]

Writes an unsigned 128 bit integer to `self` in little-endian byte order. Read more

#### `fn put_i128(&mut self, n: i128)` [src]

Writes a signed 128 bit integer to `self` in the big-endian byte order. Read more

#### `fn put_i128_le(&mut self, n: i128)` [src]

Writes a signed 128 bit integer to `self` in little-endian byte order. Read more

#### `fn put_uint(&mut self, n: u64, nbytes: usize)` [src]

Writes an unsigned n-byte integer to `self` in big-endian byte order. Read more

#### `fn put_uint_le(&mut self, n: u64, nbytes: usize)` [src]

Writes an unsigned n-byte integer to `self` in the little-endian byte order. Read more

#### `fn put_int(&mut self, n: i64, nbytes: usize)` [src]

Writes a signed n-byte integer to `self` in big-endian byte order. Read more

#### `fn put_int_le(&mut self, n: i64, nbytes: usize)` [src]

Writes a signed n-byte integer to `self` in little-endian byte order. Read more

#### `fn put_f32(&mut self, n: f32)` [src]

Writes an IEEE754 single-precision (4 bytes) floating point number to `self` in big-endian byte order. Read more

#### `fn put_f32_le(&mut self, n: f32)` [src]

Writes an IEEE754 single-precision (4 bytes) floating point number to `self` in little-endian byte order. Read more

#### `fn put_f64(&mut self, n: f64)` [src]

Writes an IEEE754 double-precision (8 bytes) floating point number to `self` in big-endian byte order. Read more

#### `fn put_f64_le(&mut self, n: f64)` [src]

Writes an IEEE754 double-precision (8 bytes) floating point number to `self` in little-endian byte order. Read more

#### `fn limit(self, limit: usize) -> Limit<Self> where
Self: Sized,` [src]

Creates an adaptor which can write at most `limit` bytes to `self`. Read more

#### `fn writer(self) -> Writer<Self>ⓘ

### Notable traits for Writer<B>

`impl<B: BufMut + Sized> Write for Writer<B>`
where
Self: Sized,` [src]

Creates an adaptor which implements the `Write` trait for `self`. Read more

#### `fn chain_mut<U: BufMut>(self, next: U) -> Chain<Self, U> where
Self: Sized,` [src]

Creates an adapter which will chain this buffer with another. Read more

### `impl Clone for BytesMut` [src]

#### `fn clone(&self) -> BytesMut` [src]

Returns a copy of the value. Read more

#### `pub fn clone_from(&mut self, source: &Self)`1.0.0 [src]

Performs copy-assignment from `source`. Read more

### `impl Debug for BytesMut` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

### `impl Default for BytesMut` [src]

#### `fn default() -> BytesMut` [src]

Returns the “default value” for a type. Read more

### `impl Deref for BytesMut` [src]

#### `type Target = [u8]`

The resulting type after dereferencing.

#### `fn deref(&self) -> &[u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Dereferences the value.

### `impl DerefMut for BytesMut` [src]

#### `fn deref_mut(&mut self) -> &mut [u8]ⓘ

### Notable traits for &'_ [u8]

`impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]`
` [src]

Mutably dereferences the value.

### `impl Drop for BytesMut` [src]

#### `fn drop(&mut self)` [src]

Executes the destructor for this type. Read more

### `impl Eq for BytesMut` [src]

### `impl<'a> Extend<&'a u8> for BytesMut` [src]

#### `fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = &'a u8>,` [src]

Extends a collection with the contents of an iterator. Read more

#### `pub fn extend_one(&mut self, item: A)` [src]

🔬 This is a nightly-only experimental API. (`extend_one`)

Extends a collection with exactly one element.

#### `pub fn extend_reserve(&mut self, additional: usize)` [src]

🔬 This is a nightly-only experimental API. (`extend_one`)

Reserves capacity in a collection for the given number of additional elements. Read more

### `impl Extend<u8> for BytesMut` [src]

#### `fn extend<T>(&mut self, iter: T) where
T: IntoIterator<Item = u8>,` [src]

Extends a collection with the contents of an iterator. Read more

#### `pub fn extend_one(&mut self, item: A)` [src]

🔬 This is a nightly-only experimental API. (`extend_one`)

Extends a collection with exactly one element.

#### `pub fn extend_reserve(&mut self, additional: usize)` [src]

🔬 This is a nightly-only experimental API. (`extend_one`)

Reserves capacity in a collection for the given number of additional elements. Read more

### `impl<'a> From<&'a [u8]> for BytesMut` [src]

#### `fn from(src: &'a [u8]) -> BytesMut` [src]

Performs the conversion.

### `impl<'a> From<&'a str> for BytesMut` [src]

#### `fn from(src: &'a str) -> BytesMut` [src]

Performs the conversion.

### `impl From<BytesMut> for Bytes` [src]

#### `fn from(src: BytesMut) -> Bytes` [src]

Performs the conversion.

### `impl<'a> FromIterator<&'a u8> for BytesMut` [src]

#### `fn from_iter<T: IntoIterator<Item = &'a u8>>(into_iter: T) -> Self` [src]

Creates a value from an iterator. Read more

### `impl FromIterator<u8> for BytesMut` [src]

#### `fn from_iter<T: IntoIterator<Item = u8>>(into_iter: T) -> Self` [src]

Creates a value from an iterator. Read more

### `impl Hash for BytesMut` [src]

#### `fn hash<H>(&self, state: &mut H) where
H: Hasher,` [src]

Feeds this value into the given `Hasher`. Read more

#### `pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,` 1.3.0 [src]

Feeds a slice of this type into the given `Hasher`. Read more

### `impl IntoIterator for BytesMut` [src]

#### `type Item = u8`

The type of the elements being iterated over.

#### `type IntoIter = IntoIter<BytesMut>`

Which kind of iterator are we turning this into?

#### `fn into_iter(self) -> Self::IntoIter` [src]

Creates an iterator from a value. Read more

### `impl<'a> IntoIterator for &'a BytesMut` [src]

#### `type Item = &'a u8`

The type of the elements being iterated over.

#### `type IntoIter = Iter<'a, u8>`

Which kind of iterator are we turning this into?

#### `fn into_iter(self) -> Self::IntoIter` [src]

Creates an iterator from a value. Read more

### `impl LowerHex for BytesMut` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter.

### `impl Ord for BytesMut` [src]

#### `fn cmp(&self, other: &BytesMut) -> Ordering` [src]

This method returns an `Ordering` between `self` and `other`. Read more

#### `#[must_use]pub fn max(self, other: Self) -> Self` 1.21.0 [src]

Compares and returns the maximum of two values. Read more

#### `#[must_use]pub fn min(self, other: Self) -> Self` 1.21.0 [src]

Compares and returns the minimum of two values. Read more

#### `#[must_use]pub fn clamp(self, min: Self, max: Self) -> Self` 1.50.0 [src]

Restrict a value to a certain interval. Read more

### `impl<'a, T: ?Sized> PartialEq<&'a T> for BytesMut where
BytesMut: PartialEq<T>,` [src]

#### `fn eq(&self, other: &&'a T) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<[u8]> for BytesMut` [src]

#### `fn eq(&self, other: &[u8]) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<Bytes> for BytesMut` [src]

#### `fn eq(&self, other: &Bytes) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<BytesMut> for BytesMut` [src]

#### `fn eq(&self, other: &BytesMut) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<BytesMut> for [u8]` [src]

#### `fn eq(&self, other: &BytesMut) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<BytesMut> for &[u8]` [src]

#### `fn eq(&self, other: &BytesMut) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<BytesMut> for Bytes` [src]

#### `fn eq(&self, other: &BytesMut) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<String> for BytesMut` [src]

#### `fn eq(&self, other: &String) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<Vec<u8, Global>> for BytesMut` [src]

#### `fn eq(&self, other: &Vec<u8>) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl PartialEq<str> for BytesMut` [src]

#### `fn eq(&self, other: &str) -> bool` [src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `#[must_use]pub fn ne(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests for `!=`.

### `impl<'a, T: ?Sized> PartialOrd<&'a T> for BytesMut where
BytesMut: PartialOrd<T>,` [src]

#### `fn partial_cmp(&self, other: &&'a T) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<[u8]> for BytesMut` [src]

#### `fn partial_cmp(&self, other: &[u8]) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<BytesMut> for BytesMut` [src]

#### `fn partial_cmp(&self, other: &BytesMut) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<BytesMut> for [u8]` [src]

#### `fn partial_cmp(&self, other: &BytesMut) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<BytesMut> for &[u8]` [src]

#### `fn partial_cmp(&self, other: &BytesMut) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<String> for BytesMut` [src]

#### `fn partial_cmp(&self, other: &String) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<Vec<u8, Global>> for BytesMut` [src]

#### `fn partial_cmp(&self, other: &Vec<u8>) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl PartialOrd<str> for BytesMut` [src]

#### `fn partial_cmp(&self, other: &str) -> Option<Ordering>` [src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `#[must_use]pub fn lt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `#[must_use]pub fn le(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `#[must_use]pub fn gt(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `#[must_use]pub fn ge(&self, other: &Rhs) -> bool` 1.0.0 [src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl Send for BytesMut` [src]

### `impl Sync for BytesMut` [src]

### `impl UpperHex for BytesMut` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter.

### `impl Write for BytesMut` [src]

#### `fn write_str(&mut self, s: &str) -> Result` [src]

Writes a string slice into this writer, returning whether the write succeeded. Read more

#### `fn write_fmt(&mut self, args: Arguments<'_>) -> Result` [src]

Glue for usage of the `write!` macro with implementors of this trait. Read more

#### `pub fn write_char(&mut self, c: char) -> Result<(), Error>`1.1.0 [src]

Writes a `char` into this writer, returning whether the write succeeded. Read more

## Auto Trait Implementations

### `impl RefUnwindSafe for BytesMut`

### `impl Unpin for BytesMut`

### `impl UnwindSafe for BytesMut`

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `pub fn to_owned(&self) -> T` [src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `pub fn clone_into(&self, target: &mut T)` [src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into`)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.