Sort Values In A Rust Vec With A Function

fn main() {
  let mut items = vec!["1.txt", "10.txt", "2.txt"];
  items.sort_by(|a, b| {
    let a_num: u32 = a.split(".").collect::<Vec<&str>>()[0].parse().expect("parse");
    let b_num: u32 = b.split(".").collect::<Vec<&str>>()[0].parse().expect("parse");
    a_num.cmp(&b_num)
  });
  dbg!(items);
}