awesome-cheatsheets/mobile/swift.swift

/********************************************************************************************
 * Swift CHEATSHEET
 * https://www.swift.org 
 ********************************************************************************************/

// Variables
  var myInt = 1
  var myExplicitInt: Int = 1 // explicit type
  var x = 1, y = 2, z = 3 // declare multiple integers
  myExplicitInt = 2 // set to another integer value

// Constants
  let myInt = 1
  myInt = 2 // compile-time error!
  
// Strings
  var myString = "a"
  let myImmutableString = "c"
  myString += "b" // ab
  myString = myString + myImmutableString // abc
  myImmutableString += "d" // compile-time error!

  let count = 7
  let message = "There are \(count) days in a week"
  Logical Operators
  var happy = true
  var sad = !happy // logical NOT, sad = false
  var everyoneHappy = happy && sad // logical AND, everyoneHappy = false
  var someoneHappy = happy || sad // logical OR, someoneHappy = true

// Printing
  let name = "swift"
  println("Hello")
  println("My name is \(name)")
  print("See you ")
  print("later")
  /*  Hello
      My name is swift
      See you later 
  */

// Arrays
  var colors = ["red", "blue"]
  var moreColors: String[] = ["orange", "purple"] // explicit type
  colors.append("green") // [red, blue, green]
  colors += "yellow" // [red, blue, green, yellow]
  colors += moreColors // [red, blue, green, yellow, orange, purple]

  var days = ["mon", "thu"]
  var firstDay = days[0] // mon
  days.insert("tue", atIndex: 1) // [mon, tue, thu]
  days[2] = "wed" // [mon, tue, wed]
  days.removeAtIndex(0) // [tue, wed]
  Dictionaries
  var days = ["mon": "monday", "tue": "tuseday"]
  days["tue"] = "tuesday" // change the value for key "tue"
  days["wed"] = "wednesday" // add a new key/value pair

  var moreDays: Dictionary = ["thu": "thursday", "fri": "friday"]
  moreDays["thu"] = nil // remove thu from the dictionary
  moreDays.removeValueForKey("fri") // remove fri from the dictionary
  Conditionals

// IF STATEMENT
  let happy = true
  if happy {
      println("We're Happy!")
  } else {
      println("We're Sad :('")
}

// We're Happy!

  let speed = 28
  if speed <= 0 {
      println("Stationary")
  } else if speed <= 30 {
      println("Safe speed")
  } else {
      println("Too fast!")
  }

// Safe speed


// SWITCH STATEMENT
  let n = 2
  switch n {
  case 1:
      println("It's 1!")
  case 2...4:
      println("It's between 2 and 4!")
  case 5, 6:
      println("It's 5 or 6")
  default:
      println("Its another number!")
  }

// It's between 2 and 4!
  For Loops
  for var index = 1; index < 3; ++index {
    // loops with index taking values 1,2 
  }
  for index in 1..3 {
    // loops with index taking values 1,2
  }
  for index in 1...3 { 
    // loops with index taking values 1,2,3
  }

  let colors = ["red", "blue", "yellow"]
  for color in colors {
      println("Color: \(color)")
  }
  // Color: red
  // Color: blue
  // Color: yellow 

  let days = ["mon": "monday", "tue": "tuesday"]
  for (shortDay, longDay) in days {
      println("\(shortDay) is short for \(longDay)")
  }
  // mon is short for monday
  // tue is short for tuesday
  While Loops
  var count = 1
  while count < 3 {
      println("count is \(count)")
      ++count
  }
  // count is 1
  // count is 2

  count = 1
  while count < 1 {
      println("count is \(count)")
      ++count
  }
  //


  count = 1
  do {
      println("count is \(count)")
      ++count
  } while count < 3
  // count is 1
  // count is 2

count = 1
do {
    println("count is \(count)")
    ++count
} while count < 1

// count is 1

// Functions
  func iAdd(a: Int, b: Int) -> Int {
    return a + b
  }
  iAdd(2, 3) // returns 5

  func eitherSide(n: Int) -> (nMinusOne: Int, nPlusOne: Int) {
    return (n-1, n+1)
  }
  eitherSide(5) // returns the tuple (4,6)

// Classes
  class Counter {
    var count: Int = 0 
    func inc() { 
      count++
    }
    func add(n: Int) {
      count += n
    }
    func printCount() {
      println("Count: \(count)")
    }
  }

  var myCount = Counter()
  myCount.inc()
  myCount.add(2)
  myCount.printCount() // Count: 3