`for`

The for loop iterates over ranges of values or the items in a collection:

fn main() {
    for x in 1..5 {
        println!("x: {x}");
    }

    for elem in [1, 2, 3, 4, 5] {
        println!("elem: {elem}");
    }
}

Under the hood for loops use a concept called “iterators” to handle iterating over different kinds of ranges/collections. Iterators will be discussed in more detail later.
請注意，for 迴圈只會疊代至 4。您可以示範 1..=5 語法，這代表含頭尾的範圍。