How do I access a variable outside of an `if let` expression?

Question

I\'m trying to access command line arguments. If the argument exists, do something, if not, do nothing. I have this code:

fn main() {
    if let Some(a) = st         


        

Answer 1

I agree that you should either do whatever you want to do inside the if-else blocks. If you just to not indent your code and your else block is small, you can inverse your if-condition.

Instead of

let arg = std::env::args().nth(2);
if let Some(a) = arg {
    let b = a;
    // do stuff
} else {
    // do other stuff
}

you can do this

let arg = std::env::args().nth(2);
if arg.is_none() {
    // do other stuff
}
let b = arg.unwrap();
// do stuff

If you want the variable to be available in the outer scope, but assign it a value in an inner scope, you can declare it outside.

let arg = std::env::args().nth(2);
let a; // declared but not assigned
if let Some(b) = arg {
    a = b; // wasn't mut but first assignment can be done here
} else {
    a = "Foobar".to_string();
}
println!("{}", a); // available here but was assigned the value inside if