Trait std::convert::Into

用于将Self类型的值转化为T类型的值，与From相反

pub trait Into<T>: Sized {
    // Required method
    fn into(self) -> T;
}

注意：此 trait 一定不能失败。如果转换可能失败，请使用 TryInto。

泛型实现

• From<T> for U 意味着 Into<U> for T
• Into 是反射的，这意味着 Into<T> for T 被实现

String 实现 Into<Vec<u8>>

fn is_hello<T: Into<Vec<u8>>>(s: T) {
   let bytes = b"hello".to_vec();
   assert_eq!(bytes, s.into());
}

let s = "hello".to_string();
is_hello(s);

为自定义类型实现Into

struct People {
    name: String,
}
impl Into<String> for People {
    fn into(self) -> String {
        self.name
    }
}

fn main() {
    let p = People {
        name: "xarzhi".to_string(),
    };
    let s: String = p.into();
    println!("{:#?}", s); // "xarzhi"
}

Required Methods

into

将此类型转换为 (通常是推断的) 输入类型。

fn into(self) -> T

Implementors

impl Into<ExitStatus> for ExitStatusError

impl<T, U> Into<U> for T

impl<T, U> Into<U> for T
where
  U: From<T>,