mirror of
https://github.com/KaiserY/trpl-zh-cn
synced 2025-02-24 21:32:15 +08:00
37 lines
1022 B
Rust
Executable File
37 lines
1022 B
Rust
Executable File
// ANCHOR: here
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fn first_word(s: &str) -> &str {
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// ANCHOR_END: here
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let bytes = s.as_bytes();
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for (i, &item) in bytes.iter().enumerate() {
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if item == b' ' {
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return &s[0..i];
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}
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}
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&s[..]
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}
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// ANCHOR: usage
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fn main() {
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let my_string = String::from("hello world");
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// `first_word` 适用于 `String`（的 slice），整体或全部
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let word = first_word(&my_string[0..6]);
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let word = first_word(&my_string[..]);
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// `first_word` 也适用于 `String` 的引用，
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// 这等价于整个 `String` 的 slice
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let word = first_word(&my_string);
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let my_string_literal = "hello world";
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// `first_word` 适用于字符串字面值，整体或全部
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let word = first_word(&my_string_literal[0..6]);
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let word = first_word(&my_string_literal[..]);
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// 因为字符串字面值已经 **是** 字符串 slice 了，
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// 这也是适用的，无需 slice 语法！
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let word = first_word(my_string_literal);
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}
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// ANCHOR_END: usage
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