Storing from inside a loop a borrowed value to container in outer scope?

Question

I set myself a little task to acquire some basic Rust knowledge. The task was:

Read some key-value pairs from stdin and put them into a hashmap.

Answer 1

In Rust 1.1 the function words was marked as deprecated. Now you should use split_whitespace.

Here is an alternative solution which is a bit more functional and idiomatic (works with 1.3).

use std::io::{self, BufRead};
use std::collections::HashMap;

fn main() {
    let stdin = io::stdin();

    // iterate over all lines, "change" the lines and collect into `HashMap`
    let map: HashMap<_, _> = stdin.lock().lines().filter_map(|line_res| {
        // convert `Result` to `Option` and map the `Some`-value to a pair of
        // `String`s
        line_res.ok().map(|line| {
            let kv: Vec<_> = line.split_whitespace().take(2).collect();
            (kv[0].to_owned(), kv[1].to_owned())
        })
    }).collect();

    println!("{}", map.len());
}