有没有更简洁的方法来格式化.expect()消息? [英] Is there a more concise way to format .expect() message?

问题描述

我目前必须使用它来格式化.expect()消息:

I currently have to use this to format a .expect() message:

fn main() {
    let x: Option<&str> = None;
    x.expect(&format!("the world is ending: {}", "foo")[..]);
}

有没有那么冗长的方式?

Is there a less verbose way?

推荐答案

首先，您不需要写[..]

如果您真的想惊慌但又想格式化错误消息，我想我会使用 assert!() :

If you really want to panic but also want to format the error message, I think I would use assert!():

fn main() {
    let x: Option<&str> = None;
    assert!(x.is_some(), "the world is ending: {}", "foo");
    let _x = x.unwrap();
}

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如果需要，您还可以使用 unwrap 板条箱:

---

If you want you could also use the unwrap crate:

use unwrap::unwrap;

fn main() {
    let x: Option<&str> = None;
    let _x = unwrap!(x, "the world is ending: {}", "foo");
}

---

此外，这两种方法都避免每次都构造错误String，这与用format!()调用expect()不同.

---

Also, both these methods avoid the construction of the error String every time, unlike calling expect() with format!().

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