comprehensive-rust/src/control-flow-basics/break-continue/labels.md

Labels

Both continue and break can optionally take a label argument which is used to break out of nested loops:

fn main() {
    let s = [[5, 6, 7], [8, 9, 10], [21, 15, 32]];
    let mut elements_searched = 0;
    let target_value = 10;
    'outer: for i in 0..=2 {
        for j in 0..=2 {
            elements_searched += 1;
            if s[i][j] == target_value {
                break 'outer;
            }
        }
    }
    print!("elements searched: {elements_searched}");
}

• Labeled break also works on arbitrary blocks, e.g.

  'label: {
      break 'label;
      println!("This line gets skipped");
  }