Swift Cheat Sheet By: Corey Leung December 18, 2017 Updated December 19, 2017 Estimated reading time: 1 minutes. Swift is a fun, fast and interactive language. We've boiled it down to the essentials in one easy to reference place. Come back to this cheat sheet anytime you need a refresher or want to confirm you're on the right path with your code. Variables var myNumber = 5 myNumber = 6 // setting the value of myNumber to now be 6 instead of 5 var myDouble:Double = 5 // explicitly defining myDouble to be a Double type Constants let myNumber = 5 myNumber = 4 // error, not allowed to mutate myNumber Types Int: A whole number ex) 5 Double: A number with more precision ex) 5.55 String: A collection of characters inside quotation marks ex) "Hello" Bool: true or false Control Flow var firstNumber = 1 var secondNumber = 1 if firstNumber == secondNumber { // write code in here to run if firstNumber is equal to secondNumber } else { // write code in here to run if firstNumber is NOT equal to secondNumber } var finalNumber = 5 for i in 1...finalNumber { print(i) } // prints the numbers 1 to 5 Functions and Methods func greet() { print("Hello!") } func greet(name:String) { print("Hello \(name)") } func greet(name:String) -> String{ return "Hello \(name)" } Arrays var scores = [74, 94, 88] scores[0] // returns 74 scores[3] // error, nothing in index 3 scores[3] = 99 // sets the value at index 3 to be 99 var scores = [Int]() // initializes a blank array where every element in this array is an Int Dictionaries var scores:[String:Int] = ["Dan": 74, "Paul": 94] scores["Tom"] = 88 //scores now has a value for the key "Tom" var scores = [String:Int]() // initializes a blank dictionary where the key is of type String, and the value is of type Int Classes class ClassName : ParentClass { let aVariable = 0 func aFunction() -> String { returns "A String" } }