For loops

Swift has a few ways of writing loops, but their underlying mechanism is the same: run some code repeatedly until a condition evaluates as false.

The most common loop in Swift is a for loop: it will loop over arrays and ranges, and each time the loop goes around it will pull out one item and assign to a constant.

For example, here’s a range of numbers:

let count = 1...10

We can use a for loop to print each item like this:

for number in count {
    print("Number is \(number)")
}

We can do the same with arrays:

let albums = ["Red", "1989", "Reputation"]

for album in albums {
    print("\(album) is on Apple Music")
}

If you don’t use the constant that for loops give you, you should use an underscore instead so that Swift doesn’t create needless values:

print("Players gonna ")

for _ in 1...5 {
    print("play")
}

SPONSORED Join a FREE crash course for iOS devs who want to become complete senior developers — from October 18th to 24th. Learn how to apply iOS app architecture patterns through a series of lectures and practical coding sessions.

Learn more

Sponsor Hacking with Swift and reach the world's largest Swift community!