切片

切片 (slice) 的作用是提供对集合 (collection) 的视图 (view):

fn main() {
    let mut a: [i32; 6] = [10, 20, 30, 40, 50, 60];
    println!("a: {a:?}");

    let s: &[i32] = &a[2..4];

    println!("s: {s:?}");
}

We create a slice by borrowing a and specifying the starting and ending indexes in brackets.
If the slice starts at index 0, Rust’s range syntax allows us to drop the starting index, meaning that &a[0..a.len()] and &a[..a.len()] are identical.
The same is true for the last index, so &a[2..a.len()] and &a[2..] are identical.
To easily create a slice of the full array, we can therefore use &a[..].
s is a reference to a slice of i32s. Notice that the type of s (&[i32]) no longer mentions the array length. This allows us to perform computation on slices of different sizes.
Slices always borrow from another object. In this example, a has to remain ‘alive’ (in scope) for at least as long as our slice.
关于修改“a[3]”的问题可能会引发一些有趣的讨论，但正解是，出于内存安全方面的原因，您无法在执行作业的这个时间点通过“a”来进行此修改，但可以从“a”和“s”安全地读取数据。它会在您创建 Slice 之前运作，在“println”之后（不再使用 Slice 时）再次运作。更多详情会在“借用检查器”部分中加以说明。

Comprehensive Rust 🦀