How can I test if a value lies within a Range?

Question

I'd like to be able to create a Range and then test if a variable is contained in that range. Something that looks like this:

fn main() {
    let a = 3..5;
    assert!(a.contains(4));
}

Right now, the only obvious thing I see is to use Iterator::any. This is ugly because it would take an O(1) operation and make it O(n):

fn main() {
    let mut a = 3..5;
    assert!(a.any(|v: i32| v == 4));
}

Answer 1

As of Rust 1.35, the original code will almost¹ compile as-is using Range::contains:

fn main() {     let a = 3..5;     assert!(a.contains(&4)); } 

¹ Passing &4 instead of 4 to contains().

Answer 2

There is nothing on Range itself (at present, anyway), but it is not difficult to do this; after all, it just takes a couple of comparisons:

4 >= a.start && 4 < a.end

Answer 3

You can use match too:

fn main() {
    let v = 132;
    match v {
        1...100 => println!("Inside"),
        _ => println!("Outside")
    }
}