for in loop in Rust

The for loop, or for-in loop, or iterator loop is used when we want to go over the elements of an iterator. This can be a fixed set of elements, but there can be also iterators where we don't know the number of elements up-front, and even iteartors that, at least theoretically, could go on indefinitely.

In this example we see two simple cases.

In the first case we iterate over the elements of a range.

In the second example we iterate over the elements of a vector.

The code

examples/for-loop/src/main.rs

fn main() {
    for i in 1..=3 {
        println!("{i}");
    }

    let animals = vec!["cat", "dog", "mouse"];
    for animal in animals {
        println!("{animal}");
    }   
}

The output

$ cargo -q run
1
2
3
cat
dog
mouse