String 类型转换

转换为字符串

To convert any type to a String is as simple as implementing the ToString trait for the type. Rather than doing so directly, you should implement the fmt::Display trait which automatically provides ToString and also allows printing the type as discussed in the section on print!.

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解析字符串

将字符串转换为其他类型很有用，其中最常见的操作之一是将字符串转换为数字。惯用的方法是使用 parse 函数，可以通过类型推断或使用"涡轮鱼"语法指定要解析的类型。以下示例展示了这两种方法。

只要为目标类型实现了 FromStr 特质，就可以将字符串转换为指定的类型。标准库中为许多类型实现了这个特质。

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要在自定义类型上获得这个功能，只需为该类型实现 FromStr 特质。

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