From Swift 1.2 onwards we have three ways of performing typecasts: as is used for typecasts that will always succeed (e.g. someString as NSString), as? is used for typecasts that might fail (e.g. someView as? UIImageView), and as! is used to force typecasts. If you use as! and you're wrong, your code will crash.
For example:
let submitButton = vw.viewWithTag(10) as! UIButton
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Other changes in Swift 1.2…
- The zip() function joins two sequences
- The flatMap() method transforms optionals and arrays
- Closures can now be marked @noescape
- Classes can now have static methods and properties
- Constants no longer require immediate initialization
- A new Set data structure
- Implicit bridging has been reduced
- Multiple if let bindings
Download all Swift 1.2 changes as a playground Link to Swift 1.2 changes
