rust - 使用 {} 在 Rust 中初始化新字符串

Question

当我尝试使用以下代码用占位符 {} 初始化字符串时:

let range_from: u32 = 1;
let range_to: u32 = 101;
let insert_message = String::new("Please input Your guess in the range from {} to {}.", range_from, range_to);
println!("{}", insert_message);
// snip
println!("{}", insert_message);

它抛出以下错误:

supplied 3 arguments| || expected 1 argument

Answer 1

String::new 不能那样做。您可以使用 format! 宏，如下所示:

let insert_message = format!("Please input Your guess in the range from {} to {}.", range_from, range_to);

或者，从 Rust 1.58 开始，您也可以这样做:

let insert_message = format!("Please input Your guess in the range from {range_from} to {range_to}.");

参见 this了解更多。