如何将单个字符的字符串转换为字符？

Question

这个问题看起来很简单，但我找不到答案。假设letter是一个单字符的字符串，如何将letter转换为char类型？

let mut letter = String::new();

io::stdin()
    .read_line(&mut letter)
    .expect("Failed to read line");

- NaeNate

---

如果您已经在使用itertools：letter.chars().exactly_one().expect("not exactly one") - Caesar

Answer 1

一种解决方案是使用chars方法。它返回一个迭代器，用于迭代字符串片段中的char。

let letter_as_char: char = letter.chars().next().unwrap();
println!("{:?}", letter_as_char);

但是需要记住的是，这很重要

。

char represents a Unicode Scalar Value, and might not match your idea of what a ‘character’ is. Iteration over grapheme clusters may be what you actually want. For example, Consider the String H

let y = "H";

let mut chars = y.chars();

assert_eq!(Some('H'), chars.next());   
assert_eq!(None, chars.next());

Now consider "y̆"

let y = "y̆";

let mut chars = y.chars();

assert_eq!(Some('y'), chars.next()); // not 'y̆'
assert_eq!(Some('\u{0306}'), chars.next());

assert_eq!(None, chars.next());

另请参阅：

• 如何在Rust中迭代Unicode图形簇？

- Abdul Niyas P M