Docs4dev
Docs
rust / latest / std / ops / enum.bound.html

Enum std::ops::Bound

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

An endpoint of a range of keys.

Examples

Bounds 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 Bounds 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

Included(T)

An inclusive bound.

Excluded(T)

An exclusive bound.

Unbounded

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

Implementations

source 
impl<T> Bound<T>
1.65.0source 
pub fn as_ref(&self) -> Bound<&T>

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

source 
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>.

source 
pub fn map<U, F>(self, f: F) -> Bound<U>
where
    F: FnOnce(T) -> U,
🔬This is a nightly-only experimental API. (bound_map #86026)

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
#![feature(bound_map)]
use std::ops::Bound::*;

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

assert_eq!(bound_string.map(|s| s.len()), Included(13));
#![feature(bound_map)]
use std::ops::Bound;
use Bound::*;

let unbounded_string: Bound<String> = Unbounded;

assert_eq!(unbounded_string.map(|s| s.len()), Unbounded);
source 
impl<T> Bound<&T>
where
    T: Clone,
1.55.0source 
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

source 
impl<T> Clone for Bound<T>
where
    T: Clone,
source 
fn clone(&self) -> Bound<T>
Returns a copy of the value. Read more
1.0.0source 
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
source 
impl<T> Debug for Bound<T>
where
    T: Debug,
source 
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
source 
impl<T> Hash for Bound<T>
where
    T: Hash,
source 
fn hash<__H>(&self, state: &mut __H)
where
    __H: Hasher,
Feeds this value into the given Hasher. Read more
1.3.0source 
fn hash_slice<H>(data: &[Self], state: &mut H)
where
    H: Hasher,
    Self: Sized,
Feeds a slice of this type into the given Hasher. Read more
source 
impl<T> PartialEq for Bound<T>
where
    T: PartialEq,
source 
fn eq(&self, other: &Bound<T>) -> bool
This method tests for self and other values to be equal, and is used by ==.
1.0.0source 
fn ne(&self, other: &Rhs) -> bool
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
source 
impl<T> Copy for Bound<T>
where
    T: Copy,
source 
impl<T> Eq for Bound<T>
where
    T: Eq,
source 
impl<T> StructuralEq for Bound<T>
source 
impl<T> StructuralPartialEq for Bound<T>

Auto Trait Implementations

impl<T> RefUnwindSafe for Bound<T>
where
    T: RefUnwindSafe,
impl<T> Send for Bound<T>
where
    T: Send,
impl<T> Sync for Bound<T>
where
    T: Sync,
impl<T> Unpin for Bound<T>
where
    T: Unpin,
impl<T> UnwindSafe for Bound<T>
where
    T: UnwindSafe,

Blanket Implementations

source 
impl<T> Any for T
where
    T: 'static + ?Sized,
source 
fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
source 
impl<T> Borrow<T> for T
where
    T: ?Sized,
source 
fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
source 
impl<T> BorrowMut<T> for T
where
    T: ?Sized,
source 
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
source 
impl<T> From<T> for T
source 
fn from(t: T) -> T

Returns the argument unchanged.

source 
impl<T, U> Into<U> for T
where
    U: From<T>,
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.

source 
impl<T> ToOwned for T
where
    T: Clone,
 
type Owned = T
The resulting type after obtaining ownership.
source 
fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
source 
fn clone_into(&self, target: &mut T)
Uses borrowed data to replace owned data, usually by cloning. Read more
source 
impl<T, U> TryFrom<U> for T
where
    U: Into<T>,
 
type Error = Infallible
The type returned in the event of a conversion error.
source 
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
source 
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.
source 
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/ops/enum.Bound.html