Enum core::ops::Bound1.17.0[−][src]

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 Bounds 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());

Run

Variants

Included(T)

包容性范围。

Excluded(T)

排他性约束。

Unbounded

无限端点。指示此方向没有界限。

Implementations

impl<T> Bound<T>

[src]

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

[src]

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

从 &Bound<T> 转换为 Bound<&T>。

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

[src]

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

从 &mut Bound<T> 转换为 Bound<&mut T>。

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

[src]

🔬 This is a nightly-only experimental API. (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

impl<T: Clone> Bound<&T>

[src]

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

1.55.0 [src]

Map 通过克隆绑定的内容将 Bound<&T> 更改为 Bound<T>。

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));