Swift version: 5.6
If you have an integer hiding inside a string, you can convert between the two just by using the integer's initializer, like this:
let myString1 = "556"
let myInt1 = Int(myString1)
Because strings might contain something that isn’t a number – e.g. “Fish” rather than “556” – the Int
initializer will return an optional integer, so if you want to force a value you should use nil coalescing like this:
let myInt2 = Int(myString) ?? 0
That means “attempt to convert myString
to an integer, but if the conversion failed because it contained something invalid then use 0 instead.”
As with other data types (Float
and Double
) it’s also possible to convert by using NSString
if you’re desperate:
let myInt3 = (myString1 as NSString).integerValue
Ideally, though, that shouldn’t needed.
SAVE 50% To celebrate Black Friday, all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 7.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
Link copied to your pasteboard.