rust - &self 和 self 有什么区别？

Question

这个问题已经有答案了:

What does the ampersand (&) before `self` mean in Rust? (1 个回答)

已关闭 去年。

我不清楚 self 之间有什么区别和&self !因为在我的示例中两者都有效。

Answer 1

&self 使用结构/枚举创建的变量被函数借用意味着未给出所有权。创建变量的函数将拥有所有权。

self 函数执行后所有权被转移，变量被销毁

struct User {
  name: String,
  id: i32
}
impl User {
    fn print_name(&self) -> () {
        println!("{}", self.name);
    }
    fn print_id(self) -> () {
        println!("{}", self.id);
    }
}

fn main() {
    let me = User { name: "Haider".to_owned(), id: 1234 };
    // me is borrowed so this means the variable is still owned by the `main` function we can call as many as functions until the ownership isn't transferred
     me.print_name();
     me.print_name();
     me.print_name();
     me.print_name();
     // ownership transferred and the `me` is destroyed after the execution of `me.print_id()` we will get error if run any other function on `me`
     me.print_id();
     // Error 
     me.print_name();

    
}