string - 替换字符串中第一次出现的模式

Question

我正在尝试编写一个 replace_first() 函数，但我找不到管理它的正确方法。

我有以下输入:

let input = "Life is Life".to_string();

我想将此类输入替换为以下浪漫输出:

My wife is Life

replace 函数替换所有出现的地方。我如何实现 replace_first 函数，以便我可以像下面这样使用它:

let input = "Life is Life".to_string();
let output = input.replace_first("Life", "My wife");
println!({}, output); // Expecting the output as "My wife is life"

Answer 1

使用replacen

Replaces first N matches of a pattern with another string.

replacen creates a new String, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice at most count times.

let input = "Life is Life".to_string();
let output = input.replacen("Life", "My wife", 1);

assert_eq!("My wife is Life", output);

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