Creating NSData from NSString in Swift

In Swift 3

let data = string.data(using: .utf8)

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In Swift 2 (or if you already have a NSString instance)

let data = string.dataUsingEncoding(NSUTF8StringEncoding)

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In Swift 1 (or if you have a swift String):

let data = (string as NSString).dataUsingEncoding(NSUTF8StringEncoding)

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Also note that data is an Optional<NSData> (since the conversion might fail), so you’ll need to unwrap it before using it, for instance:

if let d = data {
    println(d)
}