Learn Swift in One Video

Posted by Derek Banas on Jun 18, 2015 in Web Design | 0 comments

Today I’ll help you learn Swift in one video! All of the code follows the video below.

We’ll cover Data Types, Casting, If, Ternary Operator, Switch, Range, Arrays, Tuples, Dictionaries, For, While, Functions, Variadic Parameters, Pointers, Inner Functions, Closures, Structs, Computed Properties, Static, Classes, Objects, Overloading, Inheritance, Dynamic Typing, Protocols, Extensions, Generics, Enums and more.

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Code From the Video

// Comment

/*
Multiline Comment 
*/

import UIKit
import Darwin

// Variable names must start with a letter and can contain most any unicode
// character except whitespace, mathematical symbols, arrows

// Swift uses type inference to guess the data type if it isn't provided
// It assumes this is a string and won't except any other value type
var str = "Hello, playground"

// Define a constant
let pi = 3.141592

// Prints a string along with the variable value using string interpolation
println("pi is equal to \(pi)")

// You can define the data type with a type annotation
let numberOfSteps: Int = 450

// ---------- DATA TYPES ----------

// Int : Integers
// Double / Float : Decimal Numbers
// String : Characters
// Bool : true or false

// The maximum Int on a 64 bit computer
let maxInt: Int = 9223372036854775807

let maxUnsignedInt: UInt64 = UInt64.max

// The maximum Float
println("Max Float : \(FLT_MAX)")

// The maximum Double
println("Max Float : \(DBL_MAX)")

// Floats are accurate to 6 digits
let floatPrecision: Float = 1.999999 + 0.0000005
println("Float Precision: ", floatPrecision)

//Doubles are precise to 15 digits
let doublePrecision: Double = 1.99999999999999 + 0.000000000000005
println("Double Precision: ", doublePrecision)

// Booleans are either true or false
let isOver18 = true

// Create a String
let myName = "Derek"

// Combine or concatenate strings
let statement = "My name is " + myName

// Strings are immutable when you use let
// myName = "Paul"
var paulName = "Paul"
paulName = "Fred"


// ---------- CASTING ----------

// Cast a Float into an Int
println("I'm an Int now \(Int(floatPrecision))")

// Cast an Int into a Float
println("I'm a Float now \(Float(maxInt))")

// Cast an Int into a Bool
println("I'm a Bool now \(Bool(maxInt))")

// Turn a String into an Int
let myAge = "40"
let myAgeInt = myAge.toInt()

// Turn a String into a Float
let myHeight = "6.25"
let myHeightFloat = (myHeight as NSString).floatValue

// ---------- MATH ----------
println("5 + 3 =  \(5 + 3)")
println("5 - 3 =  \(5 - 3)")
println("5 * 3 =  \(5 * 3)")
println("5 / 3 =  \(5 / 3)")
println("5.3 % 3 =  \(5.3 % 3)") // Remainder Operator

// Shorthand Increment and Decrement
var num: Int = 1

println("num++ = \(num++)")
println("++num = \(++num)")

// Compound Assignment
num += 5
println("num += 5  \(num)")

num -= 5
println("num -= 5  \(num)")

num *= 5
println("num *= 5  \(num)")

num /= 5
println("num /= 5  \(num)")

num %= 5
println("num %= 5  \(num)")

// Generate random number between 0 and 10
println("Random Number : \(arc4random() % 11)")

// ---------- CONDITIONALS ----------
let age: Int = 13

// Conditional Operators > < >= <= == !=
// Logical Operators && || !

if age < 16 {
    println("You can go to school")
} else if (age >= 16) && (age < 18){
    println("You can drive")
} else {
    println("You can vote")
}

if (age < 14) || (age > 67) {
    println("You shouldn't work")
}

println("!true = \(!true)")

// Ternary Operator
var isLegalToVote: Bool = (age > 18) ? true : false

// Switch Statement
// Works with Ints, Doubles, Floats, Booleans, Strings and more
// By default after a match is made execution doesn't fall to the next
// case

let ingredient = "pinto beans"

switch ingredient {
case "pasta", "tomato":
    println("How about spaghetti")
    // fallthrough : Would check the next case if you want
case "potato":
    println("How about a baked potato")
case "pinto beans":
    println("How about a burrito")
default:
    println("A glass of water is nice")
}

// You can use a Range in switch
let testScore: Int = 89

switch testScore {
case 93...100:
    println("You got an A")
case 85...92:
    println("You got a B")
case 77...84:
    println("You got a C")
case 69...76:
    println("You got a D")
default:
    println("You got an F")
}

// ---------- ARRAYS ----------

// Every item in an array must be of the same type and
// can be Ints, Floats, Doubles, Strings, Bools, Structs

let friends: Array<String> = ["Bob", "Fred", "Paul"]

let randNums = [3, 6, 9]

// Values are referenced using indexes starting at 0
println("Random Num 1 : \(randNums[0])")

// Create empty array
var groceries = [String]()

// Add items to array
groceries.append("Tomato")
groceries.append("Potato")
groceries.append("Beans")

// How many items in array
println("Number of groceries : \(groceries.count)")

// Insert an item at an index
groceries.insert("Flour", atIndex: 1)
println(groceries)

// Replace an item
groceries[1] = "Whole Wheat Flour"
println(groceries)

// Remove an item at index
groceries.removeAtIndex(0)
println(groceries)

// Remove item by value
if let match = find(groceries,"Beans") {
    groceries.removeAtIndex(match)
}
println(groceries)

// Sort from lowest to highest
groceries = sorted(groceries, <)
println(groceries)

// Reverse array
groceries.reverse()

// Multidimensional Array
var array: [[Int]] = [[00,10,20],[01,11,21]]

for column in array {
    for row in column {
        println("\(row) : \(column)")
    }
}

println(array[1][0])


// ---------- DICTIONARIES ----------
// Use key value pairs for storing
// The key can be an Int, Double, String, Enum

// Create a dictionary
var superHeroes = [String : String]()

// Add value associated with key in brackets
superHeroes["Superman"] = "Clark Kent"

// Number of items
println("Number of Heroes : \(superHeroes.count)")

// Remove using the key
superHeroes.removeValueForKey("Superman")

// ---------- TUPLES ----------
// Tuples are normally used when you want to return 
// many values from a function

var stats = (height:6.25, weight:179, name:"Derek")
println("Height : \(stats.height)")
println("Weight : \(stats.weight)")
println("Name : \(stats.name)")

// ---------- LOOPING ----------

for var i: Int = 1; i <= 10; i++ {
    
    // If is odd skip the rest of the code in the loop
    if Bool(i % 2){
        continue
    }
    
    // If i == 10 jump out of the loop completely
    if i == 10 {
        break
    }
    
    println("\(i)")
}

// For In Loop with Range
for j in -5...5 {
    println("\(j)")
}

var quote = "I dream of a better tomorrow, where chickens can cross the road and not be questioned about their motives."

// You can cycle through strings
var numOfAs = 0
for singleChar in quote {
    if singleChar == "a"{
        numOfAs++
    }
}
println("Number of a's \(numOfAs)")

// Cycle through array with for in

let people: Array<String> = ["Bob", "Fred", "Paul"]

for person in people {
    println(person)
}

// Cycle through a Dictionary

let heroes = ["Superman" : "Clark Kent",
    "Flash" : "Barry Allen", "Batman" : "Bruce Wayne"]

for (pubName, sIdent) in heroes {
    println("\(pubName) is \(sIdent)")
}

// While Loop

var k = 0

while k <= 10 {
    println(k)
    k++
}

// Do While Loop

var l = 0

do {
    println(l)
    l++
} while l <= 10

// ---------- FUNCTIONS ----------

// Function receives no attributes and returns nothing
func sayHello(){
    println("Hello")
}

sayHello()

// Function receives an attribute
func sayHello2(name: String){
    println("Hello \(name)")
}

sayHello2("Derek")

// Receives 2 attributes and returns an Int
// Attributes are given default values
func getSum(num1: Int = 1, num2: Int = 1) -> Int {
    return num1 + num2
}

println("5 + 6 = \(getSum(num1: 5, num2: 6))")

// Variadic parameters have an unknown number of attributes
func getSum2(nums: Int...) -> Int {
    
    var sum: Int = 0
    
    for num in nums{
        sum += num
    }
    return sum
}

println("Sum : \(getSum2(1,2,3,4,5))")

// How to effect variable values outside of the function
var str1: String = "happy"
var str2: String = "sad"

func makeUppercase(inout str1: String, inout str2: String){
    str1 = str1.uppercaseString
    str2 = str2.uppercaseString
}

makeUppercase(&str1, &str2)

println(str1 + " " + str2)

// Return multiple types from function
func getMult(number: Int) -> (x2: Int, x3: Int){
    var x2 = number * 2
    var x3 = number * 3
    
    return (x2, x3)
}

var answer = getMult(50)

println(answer.x2)
println(answer.x3)

// Returning functions
// Receive an unknown number of Ints and return a Double
func average(nums: Int...) -> Double{
    var sum = 0
    
    for num in nums {
        sum += num
    }
    
    return Double(sum) / Double(nums.count)
}

func sum(nums: Int...) -> Double{
    var sum = 0
    
    for num in nums {
        sum += num
    }
    
    return Double(sum)
}

func doMath (mathOption: String) -> (Int...) -> Double{
    if mathOption == "average"{
        return average
    } else {
        return sum
    }
}

var mathFunc = doMath("average")
println(mathFunc(1,2,3,4,5,6))

mathFunc = doMath("sum")
println(mathFunc(1,2,3,4,5,6))

// Return an inner function that receives 2 Ints and
// returns a String
func multiplyIt () -> ((Int, Int) -> String) {
    func multiply(num1: Int, num2: Int) -> (String) {
        
        return "\(num1) * \(num2) = \(num1 * num2)"
    }
    return multiply
}

// Get a reference to a function that you can use to
// execute an inner function
let getValue = multiplyIt()
println(getValue(5, 3))

// ---------- CLOSURES ----------

// A Closure is self contained code like a function
// They differ in that they can be anonymous and have
// no name

// in seperates the header from the body

//{ (param: paramType, param2: paramType) -> returnType in
//    statements
//    return value
//}

// A closure that excepts and returns an Int
var square: (Int) -> (Int) = { num in
    return num * num
}

println("\(square(15))")

// Assign a closure to another variable
var squareCopy = square

println("\(squareCopy(15))")

// No attributes or returns
var sayGoodbye: () -> () = {
    println("Goodbye")
}

sayGoodbye()

// No attributes with return

var sayHappy: () -> (String) = {
    "Happy Birthday"
}

println(sayHappy())

// Reference variables outside the closure

var num3 = 3

var incrementNum = {
    println("num3 : \(++num3)")
}

incrementNum()

// An Array has a map method that excepts a closure that
// performs an action on every item in the array
let numsToSquare = [1,2,3,4,5,6]

let squaredNums = numsToSquare.map {
    (num: Int) -> String in
    "\(num * num)"
}

println(squaredNums)


// ---------- STRUCTS ----------
// You can create custom data types using Structs
// Structs are used when you don't want to inherit and
// you are modeling a simple data structure

struct Runner {
    var name: String
    var milePace: Double
    
    func displayMP() -> String {
        let absPace = Int(self.milePace)
        let prctMin = self.milePace - Double(absPace)
        let seconds = prctMin * 60
        
        return "\(absPace) min : \(seconds) sec"
    }
    
    // A computed property returns versus stores a value
    var marathonTime: Double {
        get {
            return (milePace * 26.2) / 60;
        }
    }
    
    // You can store static constants in a Struct
    static let marathonDist = 26.2;
    
}

let dennisKimetto = Runner(name: "Dennis Kimetto", milePace: 4.68)
let emmanuelMutai = Runner(name: "Emmanuel Mutai", milePace: 4.7)

println("\(dennisKimetto.name) : \(dennisKimetto.displayMP())")

println("\(emmanuelMutai.name) : \(emmanuelMutai.displayMP())")

println("Time to finish marathon : \(dennisKimetto.marathonTime) hours")

// Get a static value without initialization
println("Marathon Distance : \(Runner.marathonDist)")

// ---------- CLASSES ----------

class Animal {
    var name: String = "No Name"
    var height: Double = 0.0
    var weight: Double = 0.0
    var sound: String = "No Sound"
    
    // Assigns default values when an object is created
    // You can have many inits with different attributes
    
    // self is used to refer to attributes of the object
    // that called for this method to execute
    init(name: String, height: Double, weight: Double, sound: String){
        self.name = name
        self.height = height
        self.weight = weight
        self.sound = sound
    }
    
    func getInfo(){
        println("\(self.name) is \(self.height) cms tall and weighs \(self.weight) kgs and likes to say \(self.sound)")
    }
    
    // You can create overloaded methods if you change
    // the attributes
    func getSum(num1: Int, num2: Int) -> Int{
        return num1 + num2
    }
    
    func getSum(num1: Double, num2: Double) -> Double{
        return num1 + num2
    }
    
}

var rover = Animal(name: "Rover", height: 38, weight: 12.7, sound: "Ruff")

rover.getInfo()


// Inheritance
class Dog: Animal{
    
    // Dog can extend or override methods in Animal
    // A func marked as final can't be overridden by
    // subclasses
    
    final func digHole(){
        println("\(self.name) digs a hole")
    }
    
    override func getInfo(){
        
        // You can call a method in the superclass
        super.getInfo()
        println("and dig holes")
    }
    
}

var spot = Dog(name: "Spot", height: 38, weight: 12.7, sound: "Ruff")

// Dog inherits everything in Animal
spot.getInfo()

spot.digHole()

// You can pass any subclass type and the right method
// is automatically called
func printGetInfo(animal: Animal){
    animal.getInfo()
}

printGetInfo(rover)
printGetInfo(spot)


// You can set and get values with the dot operator
spot.name = "Doug"
println(spot.name)

// Testing overloaded methods
println("2 + 5 = \(spot.getSum(2,num2: 5))")
println("2.2 + 5.6 = \(spot.getSum(2.2,num2: 5.6))")

// Check the class type
println("Is Spot a Dog : \(spot is Animal)")

// ---------- PROTOCOLS ----------

// Protocols are like interfaces in other languages
// When you adopt a protocol you agree to define the 
// behavior it describes

protocol Flyable {
    // Define if getters and setters are available
    // Put optional before var if you want it to be 
    // optional
    var flies: Bool { get set }
    
    // You define the header for a func but nothing else
    func fly(distMiles: Double) -> String
    
}

// Adopt multiple protocols class ClassName : prot1, prot2
class Vehicle : Flyable{
    var flies: Bool = false
    var name: String = "No Name"
    
    func fly(distMiles: Double) -> String {
        if (self.flies){
            return "\(self.name) flies \(distMiles) miles"
        } else {
            return "\(self.name) can't fly"
        }
    }
}

var fordF150 = Vehicle()
fordF150.name = "Ford F-150"
fordF150.flies = false
println(fordF150.fly(10))

// ---------- EXTENSIONS ----------
// Extensions provide a way to add functionality without
// overidding existing functionality to a type being one
// you create or even Int, Double, String, Array

// Output a String as an array
extension String {
    // Array of characters
    var asArray: [Character]{
    
        // Create an empty array of characters
        var result = [Character]()
        
        // Cycle through the string and store each
        // character in the array
        for char in self {
            result.append(char)
        }
        return result
    }
    
    // We can add functions as well
    func letterOccurence(theChar: Character) -> Int{
        var numOfChars = 0
        for letter in self {
            if letter == theChar{
                numOfChars++
            }
        }
        return numOfChars
    }
    
}

var characters = "A Random string".asArray
println(characters)

var numberOfAs: Int = "a Random string".letterOccurence("a")
println("Number of As \(numberOfAs)")

// ---------- GENERICS ----------
// Generics allow you to avoid repetitive code that exists
// because of type requirements

// If we wanted to print anything other then strings
// we'd have to create many of these
func printElements(randStr: String){
    for element in randStr{
        print("\(element), ")
    }
    println()
}

printElements("A Random String")

// The <T> indicates this is a generic function
// This excepts an array of anything now

func printAnyArray<T>(anything: [T]){
    for element in anything{
        print("\(element), ")
    }
    println()
}

printAnyArray(["Paul", "Jake"])
printAnyArray([1, 2, 3])

// Now we can print out any sequence type
func printAnySeq<T: SequenceType>(anything: T){
    for element in anything{
        print("\(element), ")
    }
    println()
}

printAnySeq("A random string")

// Equatable allows you to evaluate for equality
func areTheyEqual<T: Equatable>(val1: T, val2: T) -> Bool {
    return val1 == val2
}

println(areTheyEqual(1,"b"))

// Comparable allows you to compare any data type
func compareThem<T: Comparable>(val1: T, val2: T) -> Bool {
    return val1 < val2
}

println(compareThem("a","b"))

// ---------- ENUMS ----------
// Enums structure related values and are very useful when
// you are working with a limited number of options

// Swift enums are not integer based like other languages
// They can store multiple data types

// If you want to map an enum to a value you must define 
// the data type and a value unless it is Int
enum Color: Int {
    case blue // You could also: case blue = 1
    case green
    case red
    case purple
    case yellow
    
    // Set default value to blue
    init () {
        self = .blue
    }
    
    // Create a function that returns the color
    func getData() -> String {
        switch(self){
        case .blue: return "Blue"
        case .green: return "Green"
        case .red: return "Red"
        case .purple: return "Purple"
        case .yellow: return "Yellow"
        default: return "Not Found"
        }
    }
}

var someColor = Color()

println(someColor.rawValue)

var favColor = Color.purple

// Access the value associated
println(favColor.rawValue)

if(favColor == Color.purple){
    println("Favorite Color is Purple")
}

// Call an enum function
println(favColor.getData())

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// Comment

Multiline Comment

import UIKit

import Darwin

// Variable names must start with a letter and can contain most any unicode

// character except whitespace, mathematical symbols, arrows

// Swift uses type inference to guess the data type if it isn't provided

// It assumes this is a string and won't except any other value type

var str = "Hello, playground"

// Define a constant

let pi = 3.141592

// Prints a string along with the variable value using string interpolation

println("pi is equal to \(pi)")

// You can define the data type with a type annotation

let numberOfSteps: Int = 450

// ---------- DATA TYPES ----------

// Int : Integers

// Double / Float : Decimal Numbers

// String : Characters

// Bool : true or false

// The maximum Int on a 64 bit computer

let maxInt: Int = 9223372036854775807

let maxUnsignedInt: UInt64 = UInt64.max

// The maximum Float

println("Max Float : \(FLT_MAX)")

// The maximum Double

println("Max Float : \(DBL_MAX)")

// Floats are accurate to 6 digits

let floatPrecision: Float = 1.999999 + 0.0000005

println("Float Precision: ", floatPrecision)

//Doubles are precise to 15 digits

let doublePrecision: Double = 1.99999999999999 + 0.000000000000005

println("Double Precision: ", doublePrecision)

// Booleans are either true or false

let isOver18 = true

// Create a String

let myName = "Derek"

// Combine or concatenate strings

let statement = "My name is " + myName

// Strings are immutable when you use let

// myName = "Paul"

var paulName = "Paul"

paulName = "Fred"

// ---------- CASTING ----------

// Cast a Float into an Int

println("I'm an Int now \(Int(floatPrecision))")

// Cast an Int into a Float

println("I'm a Float now \(Float(maxInt))")

// Cast an Int into a Bool

println("I'm a Bool now \(Bool(maxInt))")

// Turn a String into an Int

let myAge = "40"

let myAgeInt = myAge.toInt()

// Turn a String into a Float

let myHeight = "6.25"

let myHeightFloat = (myHeight as NSString).floatValue

// ---------- MATH ----------

println("5 + 3 = \(5 + 3)")

println("5 - 3 = \(5 - 3)")

println("5 * 3 = \(5 * 3)")

println("5 / 3 = \(5 / 3)")

println("5.3 % 3 = \(5.3 % 3)") // Remainder Operator

// Shorthand Increment and Decrement

var num: Int = 1

println("num++ = \(num++)")

println("++num = \(++num)")

// Compound Assignment

num += 5

println("num += 5 \(num)")

num -= 5

println("num -= 5 \(num)")

num *= 5

println("num *= 5 \(num)")

num /= 5

println("num /= 5 \(num)")

num %= 5

println("num %= 5 \(num)")

// Generate random number between 0 and 10

println("Random Number : \(arc4random() % 11)")

// ---------- CONDITIONALS ----------

let age: Int = 13

// Conditional Operators > < >= <= == !=

// Logical Operators && || !

if age < 16 {

println("You can go to school")

} else if (age >= 16) && (age < 18){

println("You can drive")

} else {

println("You can vote")

}

if (age < 14) || (age > 67) {

println("You shouldn't work")

}

println("!true = \(!true)")

// Ternary Operator

var isLegalToVote: Bool = (age > 18) ? true : false

// Switch Statement

// Works with Ints, Doubles, Floats, Booleans, Strings and more

// By default after a match is made execution doesn't fall to the next

// case

let ingredient = "pinto beans"

switch ingredient {

case "pasta", "tomato":

println("How about spaghetti")

// fallthrough : Would check the next case if you want

case "potato":

println("How about a baked potato")

case "pinto beans":

println("How about a burrito")

default:

println("A glass of water is nice")

}

// You can use a Range in switch

let testScore: Int = 89

switch testScore {

case 93...100:

println("You got an A")

case 85...92:

println("You got a B")

case 77...84:

println("You got a C")

case 69...76:

println("You got a D")

default:

println("You got an F")

}

// ---------- ARRAYS ----------

// Every item in an array must be of the same type and

// can be Ints, Floats, Doubles, Strings, Bools, Structs

let friends: Array<String> = ["Bob", "Fred", "Paul"]

let randNums = [3, 6, 9]

// Values are referenced using indexes starting at 0

println("Random Num 1 : \(randNums[0])")

// Create empty array

var groceries = [String]()

// Add items to array

groceries.append("Tomato")

groceries.append("Potato")

groceries.append("Beans")

// How many items in array

println("Number of groceries : \(groceries.count)")

// Insert an item at an index

groceries.insert("Flour", atIndex: 1)

println(groceries)

// Replace an item

groceries[1] = "Whole Wheat Flour"

println(groceries)

// Remove an item at index

groceries.removeAtIndex(0)

println(groceries)

// Remove item by value

if let match = find(groceries,"Beans") {

groceries.removeAtIndex(match)

}

println(groceries)

// Sort from lowest to highest

groceries = sorted(groceries, <)

println(groceries)

// Reverse array

groceries.reverse()

// Multidimensional Array

var array: [[Int]] = [[00,10,20],[01,11,21]]

for column in array {

for row in column {

println("\(row) : \(column)")

}

println(array[1][0])

// ---------- DICTIONARIES ----------

// Use key value pairs for storing

// The key can be an Int, Double, String, Enum

// Create a dictionary

var superHeroes = [String : String]()

// Add value associated with key in brackets

superHeroes["Superman"] = "Clark Kent"

// Number of items

println("Number of Heroes : \(superHeroes.count)")

// Remove using the key

superHeroes.removeValueForKey("Superman")

// ---------- TUPLES ----------

// Tuples are normally used when you want to return

// many values from a function

var stats = (height:6.25, weight:179, name:"Derek")

println("Height : \(stats.height)")

println("Weight : \(stats.weight)")

println("Name : \(stats.name)")

// ---------- LOOPING ----------

for var i: Int = 1; i <= 10; i++ {

// If is odd skip the rest of the code in the loop

if Bool(i % 2){

continue

}

// If i == 10 jump out of the loop completely

if i == 10 {

break

}

println("\(i)")

}

// For In Loop with Range

for j in -5...5 {

println("\(j)")

}

var quote = "I dream of a better tomorrow, where chickens can cross the road and not be questioned about their motives."

// You can cycle through strings

var numOfAs = 0

for singleChar in quote {

if singleChar == "a"{

numOfAs++

}

println("Number of a's \(numOfAs)")

// Cycle through array with for in

let people: Array<String> = ["Bob", "Fred", "Paul"]

for person in people {

println(person)

}

// Cycle through a Dictionary

let heroes = ["Superman" : "Clark Kent",

"Flash" : "Barry Allen", "Batman" : "Bruce Wayne"]

for (pubName, sIdent) in heroes {

println("\(pubName) is \(sIdent)")

}

// While Loop

var k = 0

while k <= 10 {

println(k)

k++

}

// Do While Loop

var l = 0

do {

println(l)

l++

} while l <= 10

// ---------- FUNCTIONS ----------

// Function receives no attributes and returns nothing

func sayHello(){

println("Hello")

}

sayHello()

// Function receives an attribute

func sayHello2(name: String){

println("Hello \(name)")

}

sayHello2("Derek")

// Receives 2 attributes and returns an Int

// Attributes are given default values

func getSum(num1: Int = 1, num2: Int = 1) -> Int {

return num1 + num2

}

println("5 + 6 = \(getSum(num1: 5, num2: 6))")

// Variadic parameters have an unknown number of attributes

func getSum2(nums: Int...) -> Int {

var sum: Int = 0

for num in nums{

sum += num

}

return sum

}

println("Sum : \(getSum2(1,2,3,4,5))")

// How to effect variable values outside of the function

var str1: String = "happy"

var str2: String = "sad"

func makeUppercase(inout str1: String, inout str2: String){

str1 = str1.uppercaseString

str2 = str2.uppercaseString

}

makeUppercase(&str1, &str2)

println(str1 + " " + str2)

// Return multiple types from function

func getMult(number: Int) -> (x2: Int, x3: Int){

var x2 = number * 2

var x3 = number * 3

return (x2, x3)

}

var answer = getMult(50)

println(answer.x2)

println(answer.x3)

// Returning functions

// Receive an unknown number of Ints and return a Double

func average(nums: Int...) -> Double{

var sum = 0

for num in nums {

sum += num

}

return Double(sum) / Double(nums.count)

}

func sum(nums: Int...) -> Double{

var sum = 0

for num in nums {

sum += num

}

return Double(sum)

}

func doMath (mathOption: String) -> (Int...) -> Double{

if mathOption == "average"{

return average

} else {

return sum

}

var mathFunc = doMath("average")

println(mathFunc(1,2,3,4,5,6))

mathFunc = doMath("sum")

println(mathFunc(1,2,3,4,5,6))

// Return an inner function that receives 2 Ints and

// returns a String

func multiplyIt () -> ((Int, Int) -> String) {

func multiply(num1: Int, num2: Int) -> (String) {

return "\(num1) * \(num2) = \(num1 * num2)"

}

return multiply

}

// Get a reference to a function that you can use to

// execute an inner function

let getValue = multiplyIt()

println(getValue(5, 3))

// ---------- CLOSURES ----------

// A Closure is self contained code like a function

// They differ in that they can be anonymous and have

// no name

// in seperates the header from the body

//{ (param: paramType, param2: paramType) -> returnType in

// statements

// return value

//}

// A closure that excepts and returns an Int

var square: (Int) -> (Int) = { num in

return num * num

}

println("\(square(15))")

// Assign a closure to another variable

var squareCopy = square

println("\(squareCopy(15))")

// No attributes or returns

var sayGoodbye: () -> () = {

println("Goodbye")

}

sayGoodbye()

// No attributes with return

var sayHappy: () -> (String) = {

"Happy Birthday"

}

println(sayHappy())

// Reference variables outside the closure

var num3 = 3

var incrementNum = {

println("num3 : \(++num3)")

}

incrementNum()

// An Array has a map method that excepts a closure that

// performs an action on every item in the array

let numsToSquare = [1,2,3,4,5,6]

let squaredNums = numsToSquare.map {

(num: Int) -> String in

"\(num * num)"

}

println(squaredNums)

// ---------- STRUCTS ----------

// You can create custom data types using Structs

// Structs are used when you don't want to inherit and

// you are modeling a simple data structure

struct Runner {

var name: String

var milePace: Double

func displayMP() -> String {

let absPace = Int(self.milePace)

let prctMin = self.milePace - Double(absPace)

let seconds = prctMin * 60

return "\(absPace) min : \(seconds) sec"

}

// A computed property returns versus stores a value

var marathonTime: Double {

get {

return (milePace * 26.2) / 60;

}

// You can store static constants in a Struct

static let marathonDist = 26.2;

}

let dennisKimetto = Runner(name: "Dennis Kimetto", milePace: 4.68)

let emmanuelMutai = Runner(name: "Emmanuel Mutai", milePace: 4.7)

println("\(dennisKimetto.name) : \(dennisKimetto.displayMP())")

println("\(emmanuelMutai.name) : \(emmanuelMutai.displayMP())")

println("Time to finish marathon : \(dennisKimetto.marathonTime) hours")

// Get a static value without initialization

println("Marathon Distance : \(Runner.marathonDist)")

// ---------- CLASSES ----------

class Animal {

var name: String = "No Name"

var height: Double = 0.0

var weight: Double = 0.0

var sound: String = "No Sound"

// Assigns default values when an object is created

// You can have many inits with different attributes

// self is used to refer to attributes of the object

// that called for this method to execute

init(name: String, height: Double, weight: Double, sound: String){

self.name = name

self.height = height

self.weight = weight

self.sound = sound

}

func getInfo(){

println("\(self.name) is \(self.height) cms tall and weighs \(self.weight) kgs and likes to say \(self.sound)")

}

// You can create overloaded methods if you change

// the attributes

func getSum(num1: Int, num2: Int) -> Int{

return num1 + num2

}

func getSum(num1: Double, num2: Double) -> Double{

return num1 + num2

}

var rover = Animal(name: "Rover", height: 38, weight: 12.7, sound: "Ruff")

rover.getInfo()

// Inheritance

class Dog: Animal{

// Dog can extend or override methods in Animal

// A func marked as final can't be overridden by

// subclasses

final func digHole(){

println("\(self.name) digs a hole")

}

override func getInfo(){

// You can call a method in the superclass

super.getInfo()

println("and dig holes")

}

var spot = Dog(name: "Spot", height: 38, weight: 12.7, sound: "Ruff")

// Dog inherits everything in Animal

spot.getInfo()

spot.digHole()

// You can pass any subclass type and the right method

// is automatically called

func printGetInfo(animal: Animal){

animal.getInfo()

}

printGetInfo(rover)

printGetInfo(spot)

// You can set and get values with the dot operator

spot.name = "Doug"

println(spot.name)

// Testing overloaded methods

println("2 + 5 = \(spot.getSum(2,num2: 5))")

println("2.2 + 5.6 = \(spot.getSum(2.2,num2: 5.6))")

// Check the class type

println("Is Spot a Dog : \(spot is Animal)")

// ---------- PROTOCOLS ----------

// Protocols are like interfaces in other languages

// When you adopt a protocol you agree to define the

// behavior it describes

protocol Flyable {

// Define if getters and setters are available

// Put optional before var if you want it to be

// optional

var flies: Bool { get set }

// You define the header for a func but nothing else

func fly(distMiles: Double) -> String

}

// Adopt multiple protocols class ClassName : prot1, prot2

class Vehicle : Flyable{

var flies: Bool = false

var name: String = "No Name"

func fly(distMiles: Double) -> String {

if (self.flies){

return "\(self.name) flies \(distMiles) miles"

} else {

return "\(self.name) can't fly"

}

var fordF150 = Vehicle()

fordF150.name = "Ford F-150"

fordF150.flies = false

println(fordF150.fly(10))

// ---------- EXTENSIONS ----------

// Extensions provide a way to add functionality without

// overidding existing functionality to a type being one

// you create or even Int, Double, String, Array

// Output a String as an array

extension String {

// Array of characters

var asArray: [Character]{

// Create an empty array of characters

var result = [Character]()

// Cycle through the string and store each

// character in the array

for char in self {

result.append(char)

}

return result

}

// We can add functions as well

func letterOccurence(theChar: Character) -> Int{

var numOfChars = 0

for letter in self {

if letter == theChar{

numOfChars++

}

return numOfChars

}

var characters = "A Random string".asArray

println(characters)

var numberOfAs: Int = "a Random string".letterOccurence("a")

println("Number of As \(numberOfAs)")

// ---------- GENERICS ----------

// Generics allow you to avoid repetitive code that exists

// because of type requirements

// If we wanted to print anything other then strings

// we'd have to create many of these

func printElements(randStr: String){

for element in randStr{

print("\(element), ")

}

println()

}

printElements("A Random String")

// The <T> indicates this is a generic function

// This excepts an array of anything now

func printAnyArray<T>(anything: [T]){

for element in anything{

print("\(element), ")

}

println()

}

printAnyArray(["Paul", "Jake"])

printAnyArray([1, 2, 3])

// Now we can print out any sequence type

func printAnySeq<T: SequenceType>(anything: T){

for element in anything{

print("\(element), ")

}

println()

}

printAnySeq("A random string")

// Equatable allows you to evaluate for equality

func areTheyEqual<T: Equatable>(val1: T, val2: T) -> Bool {

return val1 == val2

}

println(areTheyEqual(1,"b"))

// Comparable allows you to compare any data type

func compareThem<T: Comparable>(val1: T, val2: T) -> Bool {

return val1 < val2

}

println(compareThem("a","b"))

// ---------- ENUMS ----------

// Enums structure related values and are very useful when

// you are working with a limited number of options

// Swift enums are not integer based like other languages

// They can store multiple data types

// If you want to map an enum to a value you must define

// the data type and a value unless it is Int

enum Color: Int {

case blue // You could also: case blue = 1

case green

case red

case purple

case yellow

// Set default value to blue

init () {

self = .blue

}

// Create a function that returns the color

func getData() -> String {

switch(self){

case .blue: return "Blue"

case .green: return "Green"

case .red: return "Red"

case .purple: return "Purple"

case .yellow: return "Yellow"

default: return "Not Found"

}

var someColor = Color()

println(someColor.rawValue)

var favColor = Color.purple

// Access the value associated

println(favColor.rawValue)

if(favColor == Color.purple){

println("Favorite Color is Purple")

}

// Call an enum function

println(favColor.getData())

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