如何获得一个切片作为防锈静态数组？ [英] How to get a slice as a static array in rust?

问题描述

我不知道如果我使用的是正确的术语锈，所以随时纠正我在此。

I don't know if I'm using the correct Rust terminology, so feel free to correct me on this.

我有一个未知大小的数组，我想获得该数组的一个切片，将其转换为静态大小的数组：

I have an array of an unknown size, and I would like to get a slice of that array and convert it to a statically sized array:

fn pop(barry: &[u8]) -> [u8, ..3] {
    barry.slice(0, 3); // mismatched types: expected `[u8, ..3]` but found `&[u8]`
}

我会怎么做呢？

How would I do this?

推荐答案

下面是一个你要求的类型特征匹配功能。

Here's a function that matches the type signature you asked for.

fn pop(barry: &[u8]) -> [u8, ..3] {
    [barry[0], barry[1], barry[2]]
}

不过，由于巴里可以有少于三个元素，你可能要返回一个选项＆LT; U8，..三合一＆GT; 而非 [U8，..三合一] 。

But since barry could have fewer than three elements, you may want to return an Option<[u8, ..3]> rather than a [u8, ..3].

fn pop(barry: &[u8]) -> Option<[u8, ..3]> {
    if barry.len() < 3 {
        None
    } else {
        Some([barry[0], barry[1], barry[2]])
    }
}

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