Swift argument names will be derived. Since the shorthand argument is defined in expression body the 'in' keyword is omitted.
Closures as Operator Functions Swift provides an easy way to access the members by just providing operator functions as closures. In the previous examples keyword 'Bool' is used to return either 'true' when the strings are equal otherwise it returns 'false'. The expression is made even simpler by operator function in closure as let numb = [98, -20, -30, 42, 18, 35] var sortedNumbers = numb.sorted({ (left: Int, right: Int) -> Bool in return left < right }) let asc = numb.sorted(<) println(asc) When we run the above program using playground, we get the following result: [-30, -20, 18, 35, 42, 98]
Closures as Trailers Passing the function's final argument to a closure expression is declared with the help of 'Trailing Closures'. It is written outside the function () with {}. Its usage is needed when it is not possible to write the function inline on a single line. reversed = sorted(names) { $0 > $1} where {$0 > $1} are represented as trailing closures declared outside (names). import Foundation var letters = ["North", "East", "West", "South"]
let twoletters = letters.map({ (state: String) -> String in return state.substringToIndex(advance(state.startIndex, 2)).uppercaseString }) let stletters = letters.map() { $0.substringToIndex(advance($0.startIndex, 2)).uppercaseString } println(stletters)
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