How to join an array of strings in a natural way

Swift version: 5.1

Paul Hudson @twostraws October 7th 2019

Swift provides the ListFormatter class as a built-in way of joining lists of strings into a single string so that the last item has “and” before it, like a natural English string. So, rather than just getting “A, B, C” you actually get “A, B and C” – it’s much more suitable for user interfaces.

Here’s some example code:

let names = ["Ash", "Brock", "Misty"]
let joined1 = ListFormatter.localizedString(byJoining: names)
print(joined1)

That will print “Ash, Brock and Misty”. (No, there’s no way of asking it for the Oxford comma, so “Ash, Brock, and Misty” isn’t possible.)

If you want to join the strings without using the “and” at the end, you should just use the joined(separator:) method, like this:

let joined2 = names.joined(separator: ", ")
print(joined2)

That will print “Ash, Brock, Misty”.

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Available from iOS 13.0