How can I unpack (destructure) elements from a vec

问题:

I am currently doing the following:

let line_parts = line.split_whitespace().take(3).collect::<Vec<&str>>();
let ip = line_parts[0];
let bytes = line_parts[1];
let int_number = line_parts[2];

Is it possible to do something like this?

let [ip, bytes, int_number] = line.split_whitespace().take(3).collect();

I'm noticed various references to vector destructuring on some sites but the official docs don't seem to mention it.

回答1:

It seems what you need is "slice patterns":

fn main() {
    let line = "127.0.0.1 1000 what!?";
    let v = line.split_whitespace().take(3).collect::<Vec<&str>>();

    if let [ip, port, msg] = &v[..] {
         println!("{}:{} says '{}'", ip, port, msg);
    }
}

Playground link

Note the if let instead of plain let. Slice patterns are refutable, so we need to take this into account (you may want to have an else branch, too).