string 你如何逐个字符地遍历一个字符串
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How do you iterate over a string by character
提问by user2171584
I have a string and I need to scan for every occurrence of "foo" and read all the text following it until a second "
. Since Rust does not have a , I need to iterate by characters scanning for it. How would I do this?contains
function for strings
我有一个字符串,我需要扫描每次出现的“foo”并阅读它后面的所有文本,直到一秒钟"
。由于 Rust 没有,我需要通过字符扫描来迭代它。我该怎么做?contains
用于 strings的函数
Edit: Rust's &str
has a contains()
and find()
method.
编辑:Rust&str
有一个contains()
andfind()
方法。
回答by centaurian_slug
I need to iterate by characters scanning for it.
我需要通过字符扫描来迭代它。
The .chars()
methodreturns an iterator over characters in a string. e.g.
该.chars()
方法返回字符串中字符的迭代器。例如
for c in my_str.chars() {
// do something with `c`
}
for (i, c) in my_str.chars().enumerate() {
// do something with character `c` and index `i`
}
If you are interested in the byte offsets of each char, you can use char_indices
.
如果您对每个字符的字节偏移量感兴趣,可以使用char_indices
.
Look into .peekable()
, and use peek()
for looking ahead. It's wrapped like this because it supports UTF-8 codepoints instead of being a simple vector of characters.
Look into .peekable()
,peek()
用于展望未来。它是这样包装的,因为它支持 UTF-8 代码点,而不是一个简单的字符向量。
You could also create a vector of char
s and work on it from there, but that's more time and space intensive:
您也可以创建一个char
s向量并从那里开始处理它,但这需要更多的时间和空间:
let my_chars: Vec<_> = mystr.chars().collect();