# Struct hashbrown::hash_map::RawOccupiedEntryMut

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    pub struct RawOccupiedEntryMut<'a, K, V, S, A: Allocator + Clone = Global> { /* private fields */ }

Expand description

A view into an occupied entry in a `HashMap`. It is part of the `RawEntryMut` enum.

## Examples

    use core::hash::{BuildHasher, Hash};
    use hashbrown::hash_map::{HashMap, RawEntryMut, RawOccupiedEntryMut};

    let mut map = HashMap::new();
    map.extend([("a", 10), ("b", 20), ("c", 30)]);

    fn compute_hash<K: Hash + ?Sized, S: BuildHasher>(hash_builder: &S, key: &K) -> u64 {
        use core::hash::Hasher;
        let mut state = hash_builder.build_hasher();
        key.hash(&mut state);
        state.finish()
    }

    let _raw_o: RawOccupiedEntryMut<_, _, _> = map.raw_entry_mut().from_key(&"a").insert("a", 100);
    assert_eq!(map.len(), 3);

    // Existing key (insert and update)
    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => unreachable!(),
        RawEntryMut::Occupied(mut view) => {
            assert_eq!(view.get(), &100);
            let v = view.get_mut();
            let new_v = (*v) * 10;
            *v = new_v;
            assert_eq!(view.insert(1111), 1000);
        }
    }

    assert_eq!(map[&"a"], 1111);
    assert_eq!(map.len(), 3);

    // Existing key (take)
    let hash = compute_hash(map.hasher(), &"c");
    match map.raw_entry_mut().from_key_hashed_nocheck(hash, &"c") {
        RawEntryMut::Vacant(_) => unreachable!(),
        RawEntryMut::Occupied(view) => {
            assert_eq!(view.remove_entry(), ("c", 30));
        }
    }
    assert_eq!(map.raw_entry().from_key(&"c"), None);
    assert_eq!(map.len(), 2);

    let hash = compute_hash(map.hasher(), &"b");
    match map.raw_entry_mut().from_hash(hash, |q| *q == "b") {
        RawEntryMut::Vacant(_) => unreachable!(),
        RawEntryMut::Occupied(view) => {
            assert_eq!(view.remove_entry(), ("b", 20));
        }
    }
    assert_eq!(map.get(&"b"), None);
    assert_eq!(map.len(), 1);

## Implementations

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### impl<'a, K, V, S, A: Allocator + Clone> RawOccupiedEntryMut<'a, K, V, S, A>

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#### pub fn key(&self) -> &K

Gets a reference to the key in the entry.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => assert_eq!(o.key(), &"a")
    }

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#### pub fn key_mut(&mut self) -> &mut K

Gets a mutable reference to the key in the entry.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};
    use std::rc::Rc;

    let key_one = Rc::new("a");
    let key_two = Rc::new("a");

    let mut map: HashMap<Rc<&str>, u32> = HashMap::new();
    map.insert(key_one.clone(), 10);

    assert_eq!(map[&key_one], 10);
    assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);

    match map.raw_entry_mut().from_key(&key_one) {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(mut o) => {
            *o.key_mut() = key_two.clone();
        }
    }
    assert_eq!(map[&key_two], 10);
    assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);

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#### pub fn into_key(self) -> &'a mut K

Converts the entry into a mutable reference to the key in the entry with a lifetime bound to the map itself.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};
    use std::rc::Rc;

    let key_one = Rc::new("a");
    let key_two = Rc::new("a");

    let mut map: HashMap<Rc<&str>, u32> = HashMap::new();
    map.insert(key_one.clone(), 10);

    assert_eq!(map[&key_one], 10);
    assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);

    let inside_key: &mut Rc<&str>;

    match map.raw_entry_mut().from_key(&key_one) {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => inside_key = o.into_key(),
    }
    *inside_key = key_two.clone();

    assert_eq!(map[&key_two], 10);
    assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);

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#### pub fn get(&self) -> &V

Gets a reference to the value in the entry.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => assert_eq!(o.get(), &100),
    }

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#### pub fn into_mut(self) -> &'a mut V

Converts the OccupiedEntry into a mutable reference to the value in the entry with a lifetime bound to the map itself.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    let value: &mut u32;

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => value = o.into_mut(),
    }
    *value += 900;

    assert_eq!(map[&"a"], 1000);

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#### pub fn get_mut(&mut self) -> &mut V

Gets a mutable reference to the value in the entry.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(mut o) => *o.get_mut() += 900,
    }

    assert_eq!(map[&"a"], 1000);

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#### pub fn get_key_value(&self) -> (&K, &V)

Gets a reference to the key and value in the entry.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => assert_eq!(o.get_key_value(), (&"a", &100)),
    }

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#### pub fn get_key_value_mut(&mut self) -> (&mut K, &mut V)

Gets a mutable reference to the key and value in the entry.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};
    use std::rc::Rc;

    let key_one = Rc::new("a");
    let key_two = Rc::new("a");

    let mut map: HashMap<Rc<&str>, u32> = HashMap::new();
    map.insert(key_one.clone(), 10);

    assert_eq!(map[&key_one], 10);
    assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);

    match map.raw_entry_mut().from_key(&key_one) {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(mut o) => {
            let (inside_key, inside_value) = o.get_key_value_mut();
            *inside_key = key_two.clone();
            *inside_value = 100;
        }
    }
    assert_eq!(map[&key_two], 100);
    assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);

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#### pub fn into_key_value(self) -> (&'a mut K, &'a mut V)

Converts the OccupiedEntry into a mutable reference to the key and value in the entry with a lifetime bound to the map itself.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};
    use std::rc::Rc;

    let key_one = Rc::new("a");
    let key_two = Rc::new("a");

    let mut map: HashMap<Rc<&str>, u32> = HashMap::new();
    map.insert(key_one.clone(), 10);

    assert_eq!(map[&key_one], 10);
    assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);

    let inside_key: &mut Rc<&str>;
    let inside_value: &mut u32;
    match map.raw_entry_mut().from_key(&key_one) {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => {
            let tuple = o.into_key_value();
            inside_key = tuple.0;
            inside_value = tuple.1;
        }
    }
    *inside_key = key_two.clone();
    *inside_value = 100;
    assert_eq!(map[&key_two], 100);
    assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);

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#### pub fn insert(&mut self, value: V) -> V

Sets the value of the entry, and returns the entry’s old value.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(mut o) => assert_eq!(o.insert(1000), 100),
    }

    assert_eq!(map[&"a"], 1000);

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#### pub fn insert_key(&mut self, key: K) -> K

Sets the value of the entry, and returns the entry’s old value.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};
    use std::rc::Rc;

    let key_one = Rc::new("a");
    let key_two = Rc::new("a");

    let mut map: HashMap<Rc<&str>, u32> = HashMap::new();
    map.insert(key_one.clone(), 10);

    assert_eq!(map[&key_one], 10);
    assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);

    match map.raw_entry_mut().from_key(&key_one) {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(mut o) => {
            let old_key = o.insert_key(key_two.clone());
            assert!(Rc::ptr_eq(&old_key, &key_one));
        }
    }
    assert_eq!(map[&key_two], 10);
    assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);

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#### pub fn remove(self) -> V

Takes the value out of the entry, and returns it.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => assert_eq!(o.remove(), 100),
    }
    assert_eq!(map.get(&"a"), None);

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#### pub fn remove_entry(self) -> (K, V)

Take the ownership of the key and value from the map.

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => assert_eq!(o.remove_entry(), ("a", 100)),
    }
    assert_eq!(map.get(&"a"), None);

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#### pub fn replace_entry_with<F>(self, f: F) -> RawEntryMut<'a, K, V, S, A> where
F: FnOnce(&K, V) -> Option<V>,

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

##### Examples

    use hashbrown::hash_map::{HashMap, RawEntryMut};

    let mut map: HashMap<&str, u32> = [("a", 100), ("b", 200)].into();

    let raw_entry = match map.raw_entry_mut().from_key(&"a") {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => o.replace_entry_with(|k, v| {
            assert_eq!(k, &"a");
            assert_eq!(v, 100);
            Some(v + 900)
        }),
    };
    let raw_entry = match raw_entry {
        RawEntryMut::Vacant(_) => panic!(),
        RawEntryMut::Occupied(o) => o.replace_entry_with(|k, v| {
            assert_eq!(k, &"a");
            assert_eq!(v, 1000);
            None
        }),
    };
    match raw_entry {
        RawEntryMut::Vacant(_) => { },
        RawEntryMut::Occupied(_) => panic!(),
    };
    assert_eq!(map.get(&"a"), None);

## Trait Implementations

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### impl<K: Debug, V: Debug, S, A: Allocator + Clone> Debug for RawOccupiedEntryMut<'_, K, V, S, A>

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

Formats the value using the given formatter. Read more

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### impl<K, V, S, A> Send for RawOccupiedEntryMut<'_, K, V, S, A> where
K: Send,
V: Send,
S: Send,
A: Send + Allocator + Clone,

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### impl<K, V, S, A> Sync for RawOccupiedEntryMut<'_, K, V, S, A> where
K: Sync,
V: Sync,
S: Sync,
A: Sync + Allocator + Clone,

## Auto Trait Implementations

### impl<'a, K, V, S, A> RefUnwindSafe for RawOccupiedEntryMut<'a, K, V, S, A> where
A: RefUnwindSafe,
K: RefUnwindSafe,
S: RefUnwindSafe,
V: RefUnwindSafe,

### impl<'a, K, V, S, A> Unpin for RawOccupiedEntryMut<'a, K, V, S, A>

### impl<'a, K, V, S, A = Global> !UnwindSafe for RawOccupiedEntryMut<'a, K, V, S, A>

## Blanket Implementations

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### impl<T> Any for T where
T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more

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### impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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### impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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### impl<T> From<T> for T

const: unstable · source

#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

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### impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.