diff options
| -rw-r--r-- | swift.html.markdown | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/swift.html.markdown b/swift.html.markdown index a39bc1d6..df9c5092 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -149,6 +149,14 @@ var explicitEmptyMutableDictionary: [String: Float] = [:] // same as above // MARK: Control Flow // +// Condition statements support "where" clauses, which can be used +// to help provide conditions on optional values. +// Both the assignment and the "where" clause must pass. +let someNumber = Optional<Int>(7) +if let num = someNumber where num > 3 { + print("num is greater than 3") +} + // for loop (array) let myArray = [1, 1, 2, 3, 5] for value in myArray { @@ -198,7 +206,6 @@ default: // required (in order to cover all possible input) let vegetableComment = "Everything tastes good in soup." } - // // MARK: Functions // @@ -240,7 +247,7 @@ let (_, price1, _) = pricesTuple // price1 == 3.69 print(price1 == pricesTuple.1) // true print("Gas price: \(price)") -// Named tuple params +// Labeled/named tuple params func getGasPrices2() -> (lowestPrice: Double, highestPrice: Double, midPrice: Double) { return (1.77, 37.70, 7.37) } @@ -250,6 +257,18 @@ let (_, price3, _) = pricesTuple2 print(pricesTuple2.highestPrice == pricesTuple2.1) // true print("Highest gas price: \(pricesTuple2.highestPrice)") +// guard statements +func testGuard() { + // guards provide early exits or breaks, placing the error handler code near the conditions. + // it places variables it declares in the same scope as the guard statement. + guard let aNumber = Optional<Int>(7) else { + return + } + + print("number is \(aNumber)") +} +testGuard() + // Variadic Args func setup(numbers: Int...) { // its an array |