How to convert a String to an Int
Swift version: 5.2
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) ?? 0That 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).integerValueIdeally, though, that shouldn’t needed.
SPONSORED Announcing NSSpain 2020: Remote Edition! An online, continuous conference for iOS developers. We’ll start on Thursday and finish on Friday, with talks, activities, and lots of fun for 36 hours, non-stop. Sound good? Join us!
Sponsor Hacking with Swift and reach the world's largest Swift community!
Available from iOS 7.0
Similar solutions…
- Optional vs implicitly unwrapped optional: what’s the difference?
- How to add drag and drop to your app
- How to convert dates and times to a string using DateFormatter
- How to handle unknown properties and methods using @dynamicMemberLookup
- How to calculate the ROT13 of a string
About the Swift Knowledge Base
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.
