NEW: Start my new Ultimate Portfolio App course with a free Hacking with Swift+ trial! >>

Exiting multiple loops

If you put a loop inside a loop it’s called a nested loop, and it’s not uncommon to want to break out of both the inner loop and the outer loop at the same time.

As an example, we could write some code to calculate the times tables from 1 through 10 like this:

for i in 1...10 {
    for j in 1...10 {
        let product = i * j
        print ("\(i) * \(j) is \(product)")
    }
}

If we wanted to exit part-way through we need to do two things. First, we give the outside loop a label, like this:

outerLoop: for i in 1...10 {
    for j in 1...10 {
        let product = i * j
        print ("\(i) * \(j) is \(product)")
    }
}

Second, add our condition inside the inner loop, then use break outerLoop to exit both loops at the same time:

outerLoop: for i in 1...10 {
    for j in 1...10 {
        let product = i * j
        print ("\(i) * \(j) is \(product)")

        if product == 50 {
            print("It's a bullseye!")
            break outerLoop
        }
    }
}

With a regular break, only the inner loop would be exited – the outer loop would continue where it left off.

Subscribe to Hacking with Swift+

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

BUY OUR BOOKS
Buy Pro Swift Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift (Vapor Edition) Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Server-Side Swift (Kitura Edition) Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.9/5

Link copied to your pasteboard.