# Enum Bound

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    pub enum Bound<T> {
        Included(T),
        Excluded(T),
        Unbounded,
    }

🔬This is a nightly-only experimental API. (`new_range_api` #125687)
Expand description

An endpoint of a range of keys.

## §Examples

`Bound`s are range endpoints:

    use std::ops::Bound::*;
    use std::ops::RangeBounds;

    assert_eq!((..100).start_bound(), Unbounded);
    assert_eq!((1..12).start_bound(), Included(&1));
    assert_eq!((1..12).end_bound(), Excluded(&12));

Using a tuple of `Bound`s as an argument to `BTreeMap::range`. Note that in most cases, it’s better to use range syntax (`1..5`) instead.

    use std::collections::BTreeMap;
    use std::ops::Bound::{Excluded, Included, Unbounded};

    let mut map = BTreeMap::new();
    map.insert(3, "a");
    map.insert(5, "b");
    map.insert(8, "c");

    for (key, value) in map.range((Excluded(3), Included(8))) {
        println!("{key}: {value}");
    }

    assert_eq!(Some((&3, &"a")), map.range((Unbounded, Included(5))).next());

## Variants§

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### Included(T)

🔬This is a nightly-only experimental API. (`new_range_api` #125687)

An inclusive bound.

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### Excluded(T)

🔬This is a nightly-only experimental API. (`new_range_api` #125687)

An exclusive bound.

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### Unbounded

🔬This is a nightly-only experimental API. (`new_range_api` #125687)

An infinite endpoint. Indicates that there is no bound in this direction.

## Implementations§

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### impl<T> Bound<T>

1.65.0 · Source

#### pub fn as_ref(&self) -> Bound<&T>

Converts from `&Bound<T>` to `Bound<&T>`.

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#### pub fn as_mut(&mut self) -> Bound<&mut T>

🔬This is a nightly-only experimental API. (`bound_as_ref` #80996)

Converts from `&mut Bound<T>` to `Bound<&mut T>`.

1.77.0 · Source

#### pub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Bound<U>

Maps a `Bound<T>` to a `Bound<U>` by applying a function to the contained value (including both `Included` and `Excluded`), returning a `Bound` of the same kind.

##### §Examples

    use std::ops::Bound::*;

    let bound_string = Included("Hello, World!");

    assert_eq!(bound_string.map(|s| s.len()), Included(13));

    use std::ops::Bound;
    use Bound::*;

    let unbounded_string: Bound<String> = Unbounded;

    assert_eq!(unbounded_string.map(|s| s.len()), Unbounded);

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### impl<T: Clone> Bound<&T>

1.55.0 · Source

#### pub fn cloned(self) -> Bound<T>

Map a `Bound<&T>` to a `Bound<T>` by cloning the contents of the bound.

##### §Examples

    use std::ops::Bound::*;
    use std::ops::RangeBounds;

    assert_eq!((1..12).start_bound(), Included(&1));
    assert_eq!((1..12).start_bound().cloned(), Included(1));

## Trait Implementations§

1.17.0 · Source§

### impl<T: Clone> Clone for Bound<T>

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#### fn clone(&self) -> Bound<T>

Returns a duplicate of the value. Read more
1.0.0 · Source§

#### fn clone_from(&mut self, source: &Self)
where Self:,

Performs copy-assignment from `source`. Read more
1.17.0 · Source§

### impl<T: Debug> Debug for Bound<T>

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

Formats the value using the given formatter. Read more
1.17.0 · Source§

### impl<T: Hash> Hash for Bound<T>

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#### fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given `Hasher`. Read more
1.3.0 · Source§

#### fn hash_slice<H: Hasher>(data: &[Self], state: &mut H)
where Self: Sized,

Feeds a slice of this type into the given `Hasher`. Read more
1.17.0 · Source§

### impl<T: PartialEq> PartialEq for Bound<T>

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#### fn eq(&self, other: &Bound<T>) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.17.0 · Source§

### impl<T: Copy> Copy for Bound<T>

1.17.0 · Source§

### impl<T: Eq> Eq for Bound<T>

1.17.0 · Source§

### impl<T> StructuralPartialEq for Bound<T>

## Auto Trait Implementations§

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### impl<T> Freeze for Bound<T>
where T: Freeze,

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### impl<T> RefUnwindSafe for Bound<T>
where T: RefUnwindSafe,

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### impl<T> Send for Bound<T>
where T: Send,

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### impl<T> Sync for Bound<T>
where T: Sync,

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### impl<T> Unpin for Bound<T>
where T: Unpin,

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### impl<T> UnwindSafe for Bound<T>
where T: UnwindSafe,

## 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> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. 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.