`if let` Expressions

The if let expression lets you execute different code depending on whether a value matches a pattern:

use std::time::Duration;

fn sleep_for(secs: f32) {
    if let Ok(duration) = Duration::try_from_secs_f32(secs) {
        std::thread::sleep(duration);
        println!("slept for {duration:?}");
    }
}

fn main() {
    sleep_for(-10.0);
    sleep_for(0.8);
}

Unlike match, if let does not have to cover all branches. This can make it more concise than match.
A common usage is handling Some values when working with Option.
Unlike match, if let does not support guard clauses for pattern matching.
With an else clause, this can be used as an expression.