Swift version: 5.1
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 (
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.
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Available from iOS 7.0
This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.