# Enum hashbrown::hash_map::Entry [−] [src]

    pub enum Entry<'a, K, V, S> {
        Occupied(OccupiedEntry<'a, K, V, S>),
        Vacant(VacantEntry<'a, K, V, S>),
    }

A view into a single entry in a map, which may either be vacant or occupied.

This `enum` is constructed from the `entry` method on `HashMap`.

## Variants

`Occupied(OccupiedEntry<'a, K, V, S>)`

An occupied entry.

`Vacant(VacantEntry<'a, K, V, S>)`

A vacant entry.

## Implementations

### `impl<'a, K, V, S> Entry<'a, K, V, S>` [src]

#### `pub fn insert(self, value: V) -> OccupiedEntry<'a, K, V, S> where
K: Hash,
S: BuildHasher,` [src]

Sets the value of the entry, and returns an OccupiedEntry.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, u32> = HashMap::new();
    let entry = map.entry("horseyland").insert(37);

    assert_eq!(entry.key(), &"horseyland");

#### `pub fn or_insert(self, default: V) -> &'a mut V where
K: Hash,
S: BuildHasher,` [src]

Ensures a value is in the entry by inserting the default if empty, and returns a mutable reference to the value in the entry.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, u32> = HashMap::new();

    map.entry("poneyland").or_insert(3);
    assert_eq!(map["poneyland"], 3);

    *map.entry("poneyland").or_insert(10) *= 2;
    assert_eq!(map["poneyland"], 6);

#### `pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V where
K: Hash,
S: BuildHasher,` [src]

Ensures a value is in the entry by inserting the result of the default function if empty, and returns a mutable reference to the value in the entry.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, String> = HashMap::new();
    let s = "hoho".to_string();

    map.entry("poneyland").or_insert_with(|| s);

    assert_eq!(map["poneyland"], "hoho".to_string());

#### `pub fn or_insert_with_key<F: FnOnce(&K) -> V>(self, default: F) -> &'a mut V where
K: Hash,
S: BuildHasher,` [src]

Ensures a value is in the entry by inserting, if empty, the result of the default function, which takes the key as its argument, and returns a mutable reference to the value in the entry.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, usize> = HashMap::new();

    map.entry("poneyland").or_insert_with_key(|key| key.chars().count());

    assert_eq!(map["poneyland"], 9);

#### `pub fn key(&self) -> &K` [src]

Returns a reference to this entry’s key.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, u32> = HashMap::new();
    assert_eq!(map.entry("poneyland").key(), &"poneyland");

#### `pub fn and_modify<F>(self, f: F) -> Self where
F: FnOnce(&mut V),` [src]

Provides in-place mutable access to an occupied entry before any potential inserts into the map.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, u32> = HashMap::new();

    map.entry("poneyland")
       .and_modify(|e| { *e += 1 })
       .or_insert(42);
    assert_eq!(map["poneyland"], 42);

    map.entry("poneyland")
       .and_modify(|e| { *e += 1 })
       .or_insert(42);
    assert_eq!(map["poneyland"], 43);

#### `pub fn and_replace_entry_with<F>(self, f: F) -> Self where
F: FnOnce(&K, V) -> Option<V>,` [src]

Provides shared access to the key and owned access to the value of an occupied entry and allows to replace or remove it based on the value of the returned option.

# Examples

    use hashbrown::HashMap;
    use hashbrown::hash_map::Entry;

    let mut map: HashMap<&str, u32> = HashMap::new();

    let entry = map
        .entry("poneyland")
        .and_replace_entry_with(|_k, _v| panic!());

    match entry {
        Entry::Vacant(e) => {
            assert_eq!(e.key(), &"poneyland");
        }
        Entry::Occupied(_) => panic!(),
    }

    map.insert("poneyland", 42);

    let entry = map
        .entry("poneyland")
        .and_replace_entry_with(|k, v| {
            assert_eq!(k, &"poneyland");
            assert_eq!(v, 42);
            Some(v + 1)
        });

    match entry {
        Entry::Occupied(e) => {
            assert_eq!(e.key(), &"poneyland");
            assert_eq!(e.get(), &43);
        }
        Entry::Vacant(_) => panic!(),
    }

    assert_eq!(map["poneyland"], 43);

    let entry = map
        .entry("poneyland")
        .and_replace_entry_with(|_k, _v| None);

    match entry {
        Entry::Vacant(e) => assert_eq!(e.key(), &"poneyland"),
        Entry::Occupied(_) => panic!(),
    }

    assert!(!map.contains_key("poneyland"));

### `impl<'a, K, V: Default, S> Entry<'a, K, V, S>` [src]

#### `pub fn or_default(self) -> &'a mut V where
K: Hash,
S: BuildHasher,` [src]

Ensures a value is in the entry by inserting the default value if empty, and returns a mutable reference to the value in the entry.

# Examples

    use hashbrown::HashMap;

    let mut map: HashMap<&str, Option<u32>> = HashMap::new();
    map.entry("poneyland").or_default();

    assert_eq!(map["poneyland"], None);

## Trait Implementations

### `impl<K: Debug, V: Debug, S> Debug for Entry<'_, K, V, S>` [src]

#### `fn fmt(&self, f: &mut Formatter<'_>) -> Result` [src]

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl<'a, K, V, S> Send for Entry<'a, K, V, S> where
K: Send,
S: Send,
V: Send,`

### `impl<'a, K, V, S> Sync for Entry<'a, K, V, S> where
K: Sync,
S: Sync,
V: Sync,`

### `impl<'a, K, V, S> Unpin for Entry<'a, K, V, S> where
K: Unpin,`

## 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, 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.