How to use the forEach method to loop over an array

Swift version: 5.10

Paul Hudson @twostraws May 28th 2019

In Swift we normally loop over arrays like this:

let numbers = [1, 2, 3, 4, 5]

for number in numbers {
    print(number)
}

However, Swift provides us an alternative: a dedicated array method called forEach(), that loops over each item in the array and does something with it. For example, the above loop would be written like this:

numbers.forEach {
    print($0)
}

The difference is that forEach() can’t skip over any items – you can’t exit the loop part way, without processing the rest of the items. This helps people reading your code to figure out your intent: you want to act on all items, and won’t stop in the middle.