How to Use if let and while let in Rust

Use if let to run code once when a pattern matches, and while let to loop while a pattern matches.

fn main() {
    let optional = Some(5);

    if let Some(value) = optional {
        println!("Found: {value}");
    }

    let mut counter = 3;
    while let Some(n) = if counter > 0 { Some(counter) } else { None } {
        println!("Count: {n}");
        counter -= 1;
    }
}

Use if let to check if a value exists and act on it immediately, like checking if a box is open before taking something out. Use while let to keep doing something as long as the value exists, like eating cookies from a jar until it's empty. These tools make your code shorter and clearer when dealing with optional data.