将字符转换为大写 [英] Convert a char to upper case

问题描述

我有一个包含单个 char 的变量.我想将此 char 转换为大写.但是，to_uppercase 函数返回一个 rustc_unicode::char::ToUppercase 结构而不是 char.

I have a variable which contains a single char. I want to convert this char to upper case. However, the to_uppercase function returns a rustc_unicode::char::ToUppercase struct instead of a char.

推荐答案

ToUppercase 是一个迭代器，因为大写版本的字符可能由几个代码点组成，正如 delnan 在评论中指出的那样.您可以将其转换为字符向量:

ToUppercase is an iterator, because the uppercase version of the character may be composed of several codepoints, as delnan pointed in the comments. You can convert that to a Vector of characters:

c.to_uppercase().collect::<Vec<_>>();

然后，您应该按照 ker 的指示将这些字符收集到一个字符串中.

Then, you should collect those characters into a string, as ker pointed.

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