OccupiedEntry in alloc::collections::btree_set - Rust
Description: A view into an occupied entry in a `BTreeSet`. It is part of the `Entry` enum.

## OccupiedEntry

# Struct OccupiedEntry

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

🔬This is a nightly-only experimental API. (`btree_set_entry` #133549)
Expand description

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

## §Examples

    #![feature(btree_set_entry)]

    use std::collections::btree_set::{Entry, BTreeSet};

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

    let _entry_o = 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<'a, T: Ord, A: Allocator + Clone> OccupiedEntry<'a, T, A>

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

🔬This is a nightly-only experimental API. (`btree_set_entry` #133549)

Gets a reference to the value in the entry.

##### §Examples

    #![feature(btree_set_entry)]

    use std::collections::btree_set::{Entry, BTreeSet};

    let mut set = BTreeSet::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

🔬This is a nightly-only experimental API. (`btree_set_entry` #133549)

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

##### §Examples

    #![feature(btree_set_entry)]

    use std::collections::BTreeSet;
    use std::collections::btree_set::Entry;

    let mut set = BTreeSet::new();
    set.entry("poneyland").or_insert();

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

    assert_eq!(set.contains("poneyland"), false);

## Trait Implementations§

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

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

Formats the value using the given formatter. Read more

## Auto Trait Implementations§

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

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

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

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

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

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

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#### 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,

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#### 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

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

Returns the argument unchanged.

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

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#### 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>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### 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>,

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

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.