pub enum Bound<T> {
Included(T),
Excluded(T),
Unbounded,
}
Expand description
一系列键的端点。
Examples
边界是范围端点:
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));
Run使用 Bound
s 的元组作为 BTreeMap::range
的参数。
请注意,在大多数情况下,最好改用范围语法 (1..5
)。
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());
RunVariants§
Implementations§
source§impl<T> Bound<T>
impl<T> Bound<T>
sourcepub fn as_mut(&mut self) -> Bound<&mut T>
🔬This is a nightly-only experimental API. (bound_as_ref
#80996)
pub fn as_mut(&mut self) -> Bound<&mut T>
bound_as_ref
#80996)从 &mut Bound<T>
转换为 Bound<&mut T>
。
sourcepub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Bound<U>
🔬This is a nightly-only experimental API. (bound_map
#86026)
pub fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Bound<U>
bound_map
#86026)映射一个 Bound
通过将函数应用于包含的值 (包括 Included
和 Excluded
),返回相同类型的 Bound
。
Examples
#![feature(bound_map)]
use std::ops::Bound::*;
let bound_string = Included("Hello, World!");
assert_eq!(bound_string.map(|s| s.len()), Included(13));
Run#![feature(bound_map)]
use std::ops::Bound;
use Bound::*;
let unbounded_string: Bound<String> = Unbounded;
assert_eq!(unbounded_string.map(|s| s.len()), Unbounded);
Run