Bound in std::ops - Rust (original) (raw)
Enum Bound
1.17.0 · Source
pub enum Bound<T> {
Included(T),
Excluded(T),
Unbounded,
}Expand description
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());§1.17.0
An inclusive bound.
§1.17.0
An exclusive bound.
§1.17.0
An infinite endpoint. Indicates that there is no bound in this direction.
1.65.0 · Source
Converts from &Bound<T> to Bound<&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
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);🔬This is a nightly-only experimental API. (bound_copied #145966)
Map a Bound<&T> to a Bound<T> by copying the contents of the bound.
§Examples
#![feature(bound_copied)]
use std::ops::Bound::*;
use std::ops::RangeBounds;
assert_eq!((1..12).start_bound(), Included(&1));
assert_eq!((1..12).start_bound().copied(), Included(1));1.55.0 · Source
Map a Bound<&T> to a Bound<T> by cloning the contents of the bound.
§Examples
use std::ops::Bound::*;
use std::ops::RangeBounds;
let a1 = String::from("a");
let (a2, a3, a4) = (a1.clone(), a1.clone(), a1.clone());
assert_eq!(Included(&a1), (a2..).start_bound());
assert_eq!(Included(a3), (a4..).start_bound().cloned());Tests for self and other values to be equal, and is used by ==.
Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.