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Enum std::ops::Bound ​

一系列键的端点。

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

边界是范围端点：

rust
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));

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)。

rust
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());

变体 ​

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 ​

Bound<T> ​

rust
impl<T> Bound<T>

as_ref ​

从 &Bound<T> 转换为 Bound<&T>。

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

返回值：返回拥有内部引用的Bound<&T>

as_mut ​

从 &mut Bound<T> 转换为 Bound<&mut T>。

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

map ​

可以将Included 和 Excluded包含的值进行操作，然后返回出去

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

参数：

  • f：闭包函数
    • 参数为Included或Excluded包含的值，
      • 如果是Unbounded，map函数返回Unbounded，闭包函数不会执行
      • 并且声明Unbounded变量必须显示声明类型
    • 该函数的返回值

返回值：返回一个Bound，其中包含被操作过的值

参数为Included

rust
fn main() {
    use std::ops::Bound::*;

    let bound_string = Included("Hello, World!");
    let res = bound_string.map(|s| {
        println!("{:#?}", s); // "Hello, World!"
        s.len()
    });
    println!("{:#?}", res); //  Included(13)
}

参数为Excluded

rust
fn main() {
    use std::ops::Bound::*;

    let bound_string= Excluded(12);
    let res = bound_string.map(|s| {
        println!("{:?}", s); // 12
        s>10
    });
    println!("{:?}", res); //  Excluded(true)
}

参数为Unbounded

rust
fn main() {
    use std::ops::Bound::*;

    let bound_string: std::ops::Bound<usize> = Unbounded;
    let res: std::ops::Bound<usize> = bound_string.map(|s| {
		// 该函数不会执行
        println!("{:?}", s);  
        10
    });
    println!("{:?}", res); //  Unbounded
}

Bound<&T> ​

cloned ​

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

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

返回值：返回一个将 Bound<&T> 更改为 Bound<T>的副本

rust
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 ​

Clone ​

rust
impl<T> Clone for Bound<T>
where
  T: Clone,

clone ​

返回值的副本。

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

clone_from ​

从 source 执行复制分配。

rust
fn clone_from(&mut self, source : &Self)

Debug ​

rust
impl<T> Debug for Bound<T>

where

  T: Debug,

fmt ​

使用给定的格式化程序格式化该值。

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

Hash ​

rust
impl<T> Hash for Bound<T>

where

  T: Hash,

hash ​

将该值输入给定的 Hasher。

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

where

  __H: Hasher,

hash_slice ​

将这种类型的切片送入给定的 Hasher 中。

rust
fn hash_slice<H>(data: &[Self], state: &mut H)

where

  H: Hasher,

  Self: Sized,

PartialEq<Bound<T>> ​

rust
impl<T> PartialEq<Bound<T>> for Bound<T>

where

  T: PartialEq<T>,

eq ​

此方法测试 self 和 other 值是否相等，并由 == 使用。

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

ne ​

此方法测试 !=。 默认实现几乎总是足够的，并且不应在没有充分理由的情况下被覆盖。

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

Copy ​

rust
impl<T> Copy for Bound<T>
where
  T: Copy,

Eq ​

rust
impl<T> Eq for Bound<T>
where
  T: Eq,

StructuralEq ​

rust
impl<T> StructuralEq for Bound<T>

StructuralPartialEq ​

rust
impl<T> StructuralPartialEq for Bound<T>

Auto Trait Implementations ​

RefUnwindSafe ​

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

Send ​

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

Sync ​

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

Unpin ​

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

UnwindSafe ​

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

Blanket Implementations ​

Any ​

rust
impl<T> Any for T
where
  T: 'static + ?Sized,

Borrow<T> ​

rust
impl<T> Borrow<T> for T
where
  T: ?Sized,

BorrowMut<T> ​

rust
impl<T> BorrowMut<T> for T
where
  T: ?Sized,

From<T> ​

rust
impl<T> From<T> for T

Into<U> ​

rust
impl<T, U> Into<U> for T
where
  U: From<T>,

ToOwned ​

rust
impl<T> ToOwned for T
where
  T: Clone,

TryFrom<U> ​

rust
impl<T, U> TryFrom<U> for T
where
  U: Into<T>,

TryInto<U> ​

rust
impl<T, U> TryInto<U> for T
where
  U: TryFrom<T>,

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