NEW! Pre-order my latest book, Testing Swift! >>

< Previous: While loops   Next: Exiting loops >

Repeat loops

The third way of writing loops is not commonly used, but it’s so simple to learn we might as well cover it: it’s called the repeat loop, and it’s identical to a while loop except the condition to check comes at the end.

So, we could rewrite our hide and seek example like this:

var number = 1

repeat {
    print(number)
    number += 1
} while number <= 20

print("Ready or not, here I come!")

Because the condition comes at the end of the repeat loop the code inside the loop will always be executed at least once, whereas while loops check their condition before their first run.

For example, this print() function will never be run, because false is always false:

while false {
    print("This is false")
}

Xcode will even warn us that the print() line will never be executed.

On the other hand, this print() function will be run once, because repeat only fails the condition after the loop runs:

repeat {
    print("This is false")
} while false

Learn Swift faster!

Take your Swift learning to the next level: buy the Hacking with Swift e-book and get bonus material to help you learn faster!

< Previous: While loops   Next: Exiting loops >
MASTER SWIFT NOW
Buy Testing Swift Buy Practical iOS 12 Buy Pro Swift Buy Swift Design Patterns Buy Swift Coding Challenges Buy Server-Side Swift (Vapor Edition) Buy Server-Side Swift (Kitura Edition) Buy Hacking with macOS Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with Swift Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let me know!

Click here to visit the Hacking with Swift store >>