锈书 锈书的例子。 值得注意的注意事项: Chp3-Chp5:代码符号中保留关键字名称的引用名称; 例如, let r#len = 99; // lets us use `len` as a var name even though it's a reserved keyword // Slicing &some_string[..9] // Turns `String` into slice from `0` to `9` &some_string[9..] // "" "" "" from 9 to length of String &some_string[..] // Turns `String` into slice some_string.as_str() // Turns `String` into slice