如何在一个范围内包含最终值? [英] How do I include the end value in a range?

问题描述

我想创建一个带有 'a'..'z' 值(含)的向量.

I wanted to create a vector with 'a'..'z' values (inclusive).

这不会编译:

let vec: Vec<char> = ('a'..'z'+1).collect();

'a'..'z' 的惯用方式是什么?

推荐答案

Rust 1.26

从 Rust 1.26 开始，您可以使用包含范围":

Rust 1.26

As of Rust 1.26, you can use "inclusive ranges":

fn main() {
    for i in 0..=26 {
        println!("{}", i);
    }
}

Rust 1.0 到 1.25

您需要在最终值上加一个:

Rust 1.0 through 1.25

You need to add one to your end value:

fn main() {
    for i in 0..(26 + 1) {
        println!("{}", i);
    }
}

如果您需要包含所有值，这将不起作用:

This will not work if you need to include all the values:

• 如何遍历所有字节值(overflowing_literals in `0..256`)

但是，您不能遍历一系列字符:

However, you cannot iterate over a range of characters:

error[E0277]: the trait bound `char: std::iter::Step` is not satisfied
 --> src/main.rs:2:14
  |
2 |     for i in 'a'..='z'  {
  |              ^^^^^^^^^ the trait `std::iter::Step` is not implemented for `char`
  |
  = note: required because of the requirements on the impl of `std::iter::Iterator` for `std::ops::RangeInclusive<char>`

有关解决方案，请参阅为什么不能收集一系列字符?.

See Why can't a range of char be collected? for solutions.

我只想指定您感兴趣的字符集:

I would just specify the set of characters you are interested in:

static ALPHABET: &str = "abcdefghijklmnopqrstuvwxyz";

for c in ALPHABET.chars() {
    println!("{}", c);
}

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