How to convert a string to a double

Written by Paul Hudson    @twostraws

Swift strings don't have a built-in way to convert to a Double, but their NSString counterparts do. To convert between strings and doubles, just do this:

let myString = "556"
let myFloat = (myString as NSString).doubleValue

Available from iOS 7.0

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This is part of the Swift Knowledge Base, a free, searchable collection of solutions for common iOS questions.