# Struct hashbrown::hash_set::OccupiedEntry

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    pub struct OccupiedEntry<'a, T, S, A: Allocator + Clone = Global> { /* private fields */ }

Expand description

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

## Examples

    use hashbrown::hash_set::{Entry, HashSet, OccupiedEntry};

    let mut set = HashSet::new();
    set.extend(["a", "b", "c"]);

    let _entry_o: OccupiedEntry<_, _> = set.entry("a").insert();
    assert_eq!(set.len(), 3);

    // Existing key
    match set.entry("a") {
        Entry::Vacant(_) => unreachable!(),
        Entry::Occupied(view) => {
            assert_eq!(view.get(), &"a");
        }
    }

    assert_eq!(set.len(), 3);

    // Existing key (take)
    match set.entry("c") {
        Entry::Vacant(_) => unreachable!(),
        Entry::Occupied(view) => {
            assert_eq!(view.remove(), "c");
        }
    }
    assert_eq!(set.get(&"c"), None);
    assert_eq!(set.len(), 2);

## Implementations

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### impl<T, S, A: Allocator + Clone> OccupiedEntry<'_, T, S, A>

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

Gets a reference to the value in the entry.

##### Examples

    use hashbrown::hash_set::{Entry, HashSet};

    let mut set: HashSet<&str> = HashSet::new();
    set.entry("poneyland").or_insert();

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

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

Takes the value out of the entry, and returns it. Keeps the allocated memory for reuse.

##### Examples

    use hashbrown::HashSet;
    use hashbrown::hash_set::Entry;

    let mut set: HashSet<&str> = HashSet::new();
    // The set is empty
    assert!(set.is_empty() && set.capacity() == 0);

    set.entry("poneyland").or_insert();
    let capacity_before_remove = set.capacity();

    if let Entry::Occupied(o) = set.entry("poneyland") {
        assert_eq!(o.remove(), "poneyland");
    }

    assert_eq!(set.contains("poneyland"), false);
    // Now set hold none elements but capacity is equal to the old one
    assert!(set.len() == 0 && set.capacity() == capacity_before_remove);

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#### pub fn replace(self) -> T

Replaces the entry, returning the old value. The new value in the hash map will be the value used to create this entry.

##### Panics

Will panic if this OccupiedEntry was created through `Entry::insert`.

##### Examples

     use hashbrown::hash_set::{Entry, HashSet};
     use std::rc::Rc;

     let mut set: HashSet<Rc<String>> = HashSet::new();
     let key_one = Rc::new("Stringthing".to_string());
     let key_two = Rc::new("Stringthing".to_string());

     set.insert(key_one.clone());
     assert!(Rc::strong_count(&key_one) == 2 && Rc::strong_count(&key_two) == 1);

     match set.entry(key_two.clone()) {
         Entry::Occupied(entry) => {
             let old_key: Rc<String> = entry.replace();
             assert!(Rc::ptr_eq(&key_one, &old_key));
         }
         Entry::Vacant(_) => panic!(),
     }

     assert!(Rc::strong_count(&key_one) == 1 && Rc::strong_count(&key_two) == 2);
     assert!(set.contains(&"Stringthing".to_owned()));

## Trait Implementations

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### impl<T: Debug, S, A: Allocator + Clone> Debug for OccupiedEntry<'_, T, S, A>

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### impl<'a, T, S, A> RefUnwindSafe for OccupiedEntry<'a, T, S, A> where
A: RefUnwindSafe,
S: RefUnwindSafe,
T: RefUnwindSafe,

### impl<'a, T, S, A> Send for OccupiedEntry<'a, T, S, A> where
A: Send,
S: Send,
T: Send,

### impl<'a, T, S, A> Sync for OccupiedEntry<'a, T, S, A> where
A: Sync,
S: Sync,
T: Sync,

### impl<'a, T, S, A> Unpin for OccupiedEntry<'a, T, S, A> where
T: Unpin,

### impl<'a, T, S, A = Global> !UnwindSafe for OccupiedEntry<'a, T, 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.