rust - 如何将最终值包含在一个范围内？

Question

我想创建一个带有 'a'..'z' 值(含)的向量。

这不编译:

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

'a'..'z' 的惯用方式是什么？

Answer 1

使用rust 1.26

As of Rust 1.26 ，您可以使用“包含范围”:

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

Rust 1.0 到 1.25

您需要将最终值加一:

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:

• How to iterate over all byte values (overflowing_literals in `0..256`)

---

但是，您不能遍历字符范围:

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>`

参见 Why can't a range of char be collected?寻求解决方案。

我只想指定您感兴趣的字符集:

static ALPHABET: &str = "abcdefghijklmnopqrstuvwxyz";

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