Learn Swift 3 in One Video

Posted by Derek Banas on May 3, 2017 in Web Design | 0 comments

You guys asked for a Learn Swift 3 in One Video tutorial and here it is! I cover Data Types, Conditionals, Math, Strings, Arrays, Looping, Dictionaries, Tuples, Optional, Functions, Closures, Filter , Reduce, Enumerations, Structs, Classes, Inheritance, Protocols, Error Handling, Extensions and a ton more.

Like always all of the code and a transcript of the video follows the video below. On the YouTube page for this video there are time stamps that will make it easy to jump around.

If you like videos like this consider donating $1 on Patreon.

Code & Transcript

// Get current version of Swift xcrun swift -version in terminal
// File -> New -> Playground -> MacOS
// Open console -> View -> Debug Area -> Activate Console

/*
 Multiline comment
*/

// Gives access to Cocoa Framework API
import Cocoa

// Other random functions I need
import Darwin

// var declares this string variable
// Statements don't require ;
var hello = "Hello "

// You can define it is a string
var world: String = "World"

// Combine strings
var msg = hello + world

// You can place variables in print
print("Hello \(world)")

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

// Use let to define a constant
let pi = 3.14159265359

// Declare an int
var myAge: Int = 42

// Min and Max Integer Size
print("Min Int \(Int64.min)")
print("Max Int \(Int64.max)")

var pi2: Float = 3.1415
var pi3: Double = 3.1415

// Min and Max Doubles
print("Min Double \(DBL_MIN)")
print("Max Double \(DBL_MAX)")

// Max Float
print("Max Float \(Float.greatestFiniteMagnitude)")

// Booleans
var canVote: Bool = true

// Characters
var myGrade: Character = "A"

// Casting
var three: Double = 3.0
var two: Int = 2

// This would be an error without the cast
var five = three + Double(two)

// Cast to Int
print("3 : \(Int(3.14))")

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

// ----- IF / ELSE -----

// Comparison Operators : > < >= <= == !=
// === : Checks if pointing to same reference
// !== : Checks if don't point at same reference

var age: Int = 8

if age < 5 {
    print("Go to Preschool")
} else if age == 5 {
    print("Go to Kindergarten")
} else if (age > 5) && (age <= 18){
    var grade: Int = age - 5
    print("Go to Grade \(grade)")
} else {
    print("Go to College")
}

// Or logical operator
var income: Double = 12000
var gpa: Double = 3.7

print("Get Grant : \((income < 15000) || (gpa >= 3.8))")

print("")

// Not operator
print("Not True : \(!true)")

// ----- TERNARY OPERATOR -----
// Assigns 1 of 2 values depending on condition

var canDrive: Bool = age >= 16 ? true : false

// ----- SWITCH -----
// Matches a limited number of values and doesn't all
// through after a match

let ingredient = "pasta"

switch ingredient {
    // Matches for tomatoes or pasta
    case "tomatoes", "pasta":
        print("Spaghetti")
        // fallthrough matches the next case even if 
        // there is no match
    case "beans":
        print("Burrito")
    case "potatoes":
        print("Mashed Potatoes")
    default:
        print("Water")
}

// You can also match ranges
let testScore: Int = 89
        
switch testScore {
    case 93...100:
        print("You got an A")
    case 85...92:
        print("You got a B")
    case 77...84:
        print("You got a C")
    case 69...76:
        print("You got a D")
    default:
        print("You got an F")
}

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

print("5 + 4 = \(5 + 4)")
print("5 - 4 = \(5 - 4)")
print("5 * 4 = \(5 * 4)")
print("5.0 / 4.0 = \(5.0 / 4.0)")
print("5 % 4 = \(5 % 4)")

// ----- ORDER OF OPERATIONS -----
print("4 + 5 * 10 = \(4 + 5 * 10)")
print("(4 + 5) * 10 = \((4 + 5) * 10)")

// Shortcuts
var randNum: Int = 5
randNum += 1
randNum -= 1

// You can't do randNum++ in Swift 3?

// Math Functions
print("abs(-5) = \(abs(-5))")
print("floor(5.5) = \(floor(5.5))")
print("ceil(5.4) = \(ceil(5.4))")
print("max(5,4) = \(max(5,4))")
print("min(5,4) = \(min(5,4))")
print("pow(5,2) = \(pow(5,2))")
print("sqrt(25) = \(sqrt(25))")
print("log(2.71828) = \(log(2.71828))")

// There is also sin, cos, tan, asin, acos, atan
// sinh, cosh, tanh

// ----- STRINGS -----
// A string of characters that are passed by value
// Escape Characters : \\ \t \n \" \'
var randStr = "This is a random string"
var randStr2 = " and here is another"

// Join strings
var randStr3 = randStr + randStr2

// String length
print("Length : \(randStr3.characters.count)")

// Get the first character
print("First : \(randStr3[randStr3.startIndex])")

// Get the 5th character
let index5 = randStr3.index(randStr3.startIndex, offsetBy: 5)
print("5th : \(randStr3[index5])")

// Check if string is empty
print("Empty : \(randStr.isEmpty)")

// Insert a character at an index
randStr2.insert("A", at: randStr2.startIndex)

// Insert a string at an index
randStr2.insert(contentsOf: " string ".characters, at: randStr2.index(randStr2.startIndex, offsetBy: 2))
print(randStr2)

// Get a substring
let startIndex = randStr2.index(randStr2.startIndex, offsetBy: 2)
let endIndex = randStr2.index(randStr2.startIndex, offsetBy: 9)
let stringRange = startIndex ..< endIndex
let subStr = randStr2.substring(with: stringRange)

// Replace a string
// Check if there is a match
if let hereMatch = randStr2.range(of: "here"){
    randStr2.replaceSubrange(hereMatch, with: "there")
}
print(randStr2)

// ----- ARRAYS -----
// Stores values of the same type

// Make empty array
var array1 = [Int]()

// Check if array is empty
print("Empty \(array1.isEmpty)")

// Add value to array
array1.append(5)

// Add another item
array1 += [7, 9]

// Get array item
print("Index 1 : \(array1[1])")

// Change value at index
array1[0] = 4

// Insert at an index
array1.insert(10, at: 3)

// Remove item
array1.remove(at: 3)

// Change multiple values
array1[0...2] = [1,2,3]

// Length of array
print("Length : \(array1.count)")

// Fill array with a value
var array2 = Array(repeating: 0, count: 5)

// Combine arrays
var array3 = array1 + array2

// Iterate through an array
for item in array3 {
    print(item)
}

// Get index and value
for (index, value) in array3.enumerated() {
    print("\(index) : \(value)")
}

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

// ----- FOR LOOP -----

var array4 = [1,2,3]

// Iterate through array
for item in array4 {
    print(item)
}

// Iterate with a range
for i in 1...5 {
    print(i)
}

// ----- WHERE -----
// Print only evens
for i in 1...10 where i % 2 == 0 {
    print("Even : \(i)")
}

// ----- WHILE LOOP -----
var i: Int = 1
while i < 10 {
    
    if i % 2 == 0 {
        i += 1
        
        // Continue jumps back to the beginning of the loop
        continue
    }
    
    if i == 7 {
        
        // Break ends the loop
        break
    }
    
    print(i)
    i += 1
}

// ----- REPEAT WHILE -----

// Generate a random number
let magicNum: UInt32 = arc4random_uniform(10)
var guess: UInt32 = 0

/*
repeat {
    print("Guess : \(guess)")
    guess += 1
} while (magicNum != guess)

print("Magic Number was \(magicNum)")
 
*/

// ----- DICTIONARIES -----
// Stores unordered lists of key value pairs

// Create empty dictionary
var dict1 = [Int: String]()

// Check if empty
print("Empty : \(dict1.isEmpty)")

// Create an item with index of 1
dict1[1] = "Paul Smith"

// Create a dictionary with a string key
var cust: [String: String] = ["1": "Sally Marks", "2": "Paul Marks"]

// Size of dictionary
print("Size : \(cust.count)")

// Add an item
cust["3"] = "Doug Holmes"

// Change a value
cust["3"] = "Doug Marks"

// Get a value
if let name = cust["3"] {
    print("Index 3 : \(name)")
}

// Remove a key value pair
cust["3"] = nil

// Iterate through a dictionary
for (key, value) in cust {
    print("\(key) : \(value)")
}

// ----- TUPLES -----
// Tuples are finite group of values that are related

let height: Double = 6.25
let weight: Int = 175

// Create a tuple
let myData = (height, weight)

// Access values
print("Height : \(myData.0)")

// You can name values
let myData2 = (height: 6.25, weight: 175)

print("Weight : \(myData2.weight)")

// ----- OPTIONAL -----
// Optionals are used to indicate that there may
// not be a value. Everything that can have a 
// value of nil should be declared optional

// Declare an optional
var politicalParty: String?
politicalParty = "Independent"

// Check for nil
if politicalParty != nil {
    
    // Get the value (Forced Unwrapping)
    let party = politicalParty!
    print("Party : \(party)")
}

// Optional binding is used to check if an optional 
// has a value
if let party = politicalParty {
    print("Party : \(party)")
} else {
    print("No Party")
}

// If nil use coalescing operator to assign a value
let party = politicalParty ?? "No Party"

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

// Define your parameter types
func getSum(num1: Int, num2: Int){
    print("Sum : \(num1 + num2)")
}

getSum(num1: 5,num2: 6)

// Define your return type and you can define
// default values
func getSum2(num1: Int, num2: Int = 1) -> Int{
    return num1 + num2
}

print("Sum : \(getSum2(num1: 8, num2: 6))")

// A variadic parameter allows for an unknown
// number of parameters
func getSum3(nums: Int...) -> Int{
    var sum: Int = 0
    for num in nums {
        sum += num
    }
    return sum
}

print("Sum : \(getSum3(nums: 1,2,3,4,5))")

// Nested functions are only callable by the enclosing
// function

func doMath(num1: Double, num2: Double){
    func mult() -> Double{
        return num1 / num2
    }
    
    print("Mult : \(mult())")
}

doMath(num1: 5.0, num2: 6.0)

// Return multiple values
func twoMults(num: Int) -> (two: Int, three: Int){
    let two: Int = num * 2
    let three: Int = num * 3
    return (two, three)
}

let mults = twoMults(num: 2)

print("2 Mults : \(mults.two), \(mults.three)")

// ----- CLOSURES -----
// Closures are functions that don't require a name 
// or function definition

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

print("5 Quared : \(square(5))")

// Assign a closure to another variable
var squareCopy = square
print("5 Quared : \(squareCopy(5))")

// You can reference any values outside the closure
let numbers = [8,9,2,4,1,0,7]

// Create a function that returns a Bool stating
// if 1 value is greater then the other

let sortedNums = numbers.sorted(by: {
    x, y in x < y
})

for i in sortedNums{
    print(i)
}

// Square every item in an array with map
// map excepts a closure

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

print(squaredNums)

// Return a function

func funcMaker(val: Int) -> (Int) -> Int {
    func addVals(num1: Int) -> Int{
        return num1 + val
    }
    
    return addVals
}

let add4 = funcMaker(val: 4)

print("4 + 5 = \(add4(5))")

// Pass a function as a parameter
func doMath2(_ mathFunc: (Int, Int) -> Int, val: Int){
    print("Sum : \(mathFunc(val, val))")
}

func addNums(a: Int, b: Int) -> Int {
    return a + b
}

doMath2(addNums, val: 5)

// ----- FILTER -----
// Used to filter out values in an array
let nums2 = [1,2,3,4,5,6]

let evenNums = nums2.filter{
    (num: Int) -> Bool in
    return num % 2 == 0
}

print(evenNums)

// ----- REDUCE -----
// Reduces array values into one value
let sum2 = nums2.reduce(0) {
    (x: Int, y: Int) -> Int in
    return x + y
}

print(sum2)

// ----- ENUMERATIONS -----
// Define types with a limited number of cases

enum Emotion {
    case joy
    case anger
    case fear
    case disgust
    case sad
}

var feeling = Emotion.joy

// change the value
feeling = .anger

// Check value
print("Angry : \(feeling == .anger)")

// ----- STRUCTS -----
// Structs group related data together

struct Rectangle {
    var height = 0.0
    var length = 0.0
    
    // You can include functions
    func area() -> Double{
        let area = height * length
        return area
    }
}

// Create a Rectangle
let myRect = Rectangle(height: 10.0, length: 5.0)

print("Area : \(myRect.height) * \(myRect.length) = \(myRect.area())")

// ----- 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(){
        print("\(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(){
        print("\(self.name) digs a hole")
    }
    
    override func getInfo(){
        
        // You can call a method in the superclass
        super.getInfo()
        print("and digs 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(animal: rover)
printGetInfo(animal: spot)


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

// Testing overloaded methods
print("2 + 5 = \(spot.getSum(num1: 2,num2: 5))")
print("2.2 + 5.6 = \(spot.getSum(num1: 2.2,num2: 5.6))")

// Check the class type
print("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
print(fordF150.fly(distMiles: 10))

// ----- ERROR HANDLING -----
// Used to handle errors gracefully

// Define our error by defining a type of the Error protocol

enum DivisionError: Error{
    case DivideByZero
}

// Define we want the error to get thrown from the function
func divide(num1: Float, num2: Float) throws -> Float {
    guard num2 != 0.0 else {
        throw DivisionError.DivideByZero
    }
    return num1/num2
}

// Wrap code that could trigger an error in a do catch block
// catch the error and handle it

do {
    try divide(num1: 4, num2: 0)
} catch DivisionError.DivideByZero {
    print("Can't Divide by Zero")
}

// ----- EXTENSIONS -----
// Extensions add new functionality to existing classes, structs
// and other types

// Extend a Double to work with different distance units
// The Double by default is in meters and we can convert
// to other types by appending a dot syntax

extension Double {
    var km: Double { return self * 1000.0 }
    var m: Double { return self }
    var ft: Double { return self * 3.28 }
    var inch: Double { return self * 39.37}
    
    // Add a method to Double for squares
    mutating func square() -> Double {
        let sqr = self * self
        return sqr
    }
}

// Convert 1 meter into inches
let oneMeter = 1.0.inch
print("One Meter is \(oneMeter) inches")

// Get the square
var randNum2: Double = 5
print("Square of 5 : \(randNum2.square())")

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// Get current version of Swift xcrun swift -version in terminal

// File -> New -> Playground -> MacOS

// Open console -> View -> Debug Area -> Activate Console

Multiline comment

// Gives access to Cocoa Framework API

import Cocoa

// Other random functions I need

import Darwin

// var declares this string variable

// Statements don't require ;

var hello = "Hello "

// You can define it is a string

var world: String = "World"

// Combine strings

var msg = hello + world

// You can place variables in print

print("Hello \(world)")

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

// Use let to define a constant

let pi = 3.14159265359

// Declare an int

var myAge: Int = 42

// Min and Max Integer Size

print("Min Int \(Int64.min)")

print("Max Int \(Int64.max)")

var pi2: Float = 3.1415

var pi3: Double = 3.1415

// Min and Max Doubles

print("Min Double \(DBL_MIN)")

print("Max Double \(DBL_MAX)")

// Max Float

print("Max Float \(Float.greatestFiniteMagnitude)")

// Booleans

var canVote: Bool = true

// Characters

var myGrade: Character = "A"

// Casting

var three: Double = 3.0

var two: Int = 2

// This would be an error without the cast

var five = three + Double(two)

// Cast to Int

print("3 : \(Int(3.14))")

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

// ----- IF / ELSE -----

// Comparison Operators : > < >= <= == !=

// === : Checks if pointing to same reference

// !== : Checks if don't point at same reference

var age: Int = 8

if age < 5 {

print("Go to Preschool")

} else if age == 5 {

print("Go to Kindergarten")

} else if (age > 5) && (age <= 18){

var grade: Int = age - 5

print("Go to Grade \(grade)")

} else {

print("Go to College")

}

// Or logical operator

var income: Double = 12000

var gpa: Double = 3.7

print("Get Grant : \((income < 15000) || (gpa >= 3.8))")

print("")

// Not operator

print("Not True : \(!true)")

// ----- TERNARY OPERATOR -----

// Assigns 1 of 2 values depending on condition

var canDrive: Bool = age >= 16 ? true : false

// ----- SWITCH -----

// Matches a limited number of values and doesn't all

// through after a match

let ingredient = "pasta"

switch ingredient {

// Matches for tomatoes or pasta

case "tomatoes", "pasta":

print("Spaghetti")

// fallthrough matches the next case even if

// there is no match

case "beans":

print("Burrito")

case "potatoes":

print("Mashed Potatoes")

default:

print("Water")

}

// You can also match ranges

let testScore: Int = 89

switch testScore {

case 93...100:

print("You got an A")

case 85...92:

print("You got a B")

case 77...84:

print("You got a C")

case 69...76:

print("You got a D")

default:

print("You got an F")

}

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

print("5 + 4 = \(5 + 4)")

print("5 - 4 = \(5 - 4)")

print("5 * 4 = \(5 * 4)")

print("5.0 / 4.0 = \(5.0 / 4.0)")

print("5 % 4 = \(5 % 4)")

// ----- ORDER OF OPERATIONS -----

print("4 + 5 * 10 = \(4 + 5 * 10)")

print("(4 + 5) * 10 = \((4 + 5) * 10)")

// Shortcuts

var randNum: Int = 5

randNum += 1

randNum -= 1

// You can't do randNum++ in Swift 3?

// Math Functions

print("abs(-5) = \(abs(-5))")

print("floor(5.5) = \(floor(5.5))")

print("ceil(5.4) = \(ceil(5.4))")

print("max(5,4) = \(max(5,4))")

print("min(5,4) = \(min(5,4))")

print("pow(5,2) = \(pow(5,2))")

print("sqrt(25) = \(sqrt(25))")

print("log(2.71828) = \(log(2.71828))")

// There is also sin, cos, tan, asin, acos, atan

// sinh, cosh, tanh

// ----- STRINGS -----

// A string of characters that are passed by value

// Escape Characters : \\ \t \n \" \'

var randStr = "This is a random string"

var randStr2 = " and here is another"

// Join strings

var randStr3 = randStr + randStr2

// String length

print("Length : \(randStr3.characters.count)")

// Get the first character

print("First : \(randStr3[randStr3.startIndex])")

// Get the 5th character

let index5 = randStr3.index(randStr3.startIndex, offsetBy: 5)

print("5th : \(randStr3[index5])")

// Check if string is empty

print("Empty : \(randStr.isEmpty)")

// Insert a character at an index

randStr2.insert("A", at: randStr2.startIndex)

// Insert a string at an index

randStr2.insert(contentsOf: " string ".characters, at: randStr2.index(randStr2.startIndex, offsetBy: 2))

print(randStr2)

// Get a substring

let startIndex = randStr2.index(randStr2.startIndex, offsetBy: 2)

let endIndex = randStr2.index(randStr2.startIndex, offsetBy: 9)

let stringRange = startIndex ..< endIndex

let subStr = randStr2.substring(with: stringRange)

// Replace a string

// Check if there is a match

if let hereMatch = randStr2.range(of: "here"){

randStr2.replaceSubrange(hereMatch, with: "there")

}

print(randStr2)

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

// Stores values of the same type

// Make empty array

var array1 = [Int]()

// Check if array is empty

print("Empty \(array1.isEmpty)")

// Add value to array

array1.append(5)

// Add another item

array1 += [7, 9]

// Get array item

print("Index 1 : \(array1[1])")

// Change value at index

array1[0] = 4

// Insert at an index

array1.insert(10, at: 3)

// Remove item

array1.remove(at: 3)

// Change multiple values

array1[0...2] = [1,2,3]

// Length of array

print("Length : \(array1.count)")

// Fill array with a value

var array2 = Array(repeating: 0, count: 5)

// Combine arrays

var array3 = array1 + array2

// Iterate through an array

for item in array3 {

print(item)

}

// Get index and value

for (index, value) in array3.enumerated() {

print("\(index) : \(value)")

}

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

// ----- FOR LOOP -----

var array4 = [1,2,3]

// Iterate through array

for item in array4 {

print(item)

}

// Iterate with a range

for i in 1...5 {

print(i)

}

// ----- WHERE -----

// Print only evens

for i in 1...10 where i % 2 == 0 {

print("Even : \(i)")

}

// ----- WHILE LOOP -----

var i: Int = 1

while i < 10 {

if i % 2 == 0 {

i += 1

// Continue jumps back to the beginning of the loop

continue

}

if i == 7 {

// Break ends the loop

break

}

print(i)

i += 1

}

// ----- REPEAT WHILE -----

// Generate a random number

let magicNum: UInt32 = arc4random_uniform(10)

var guess: UInt32 = 0

repeat {

print("Guess : \(guess)")

guess += 1

} while (magicNum != guess)

print("Magic Number was \(magicNum)")

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

// Stores unordered lists of key value pairs

// Create empty dictionary

var dict1 = [Int: String]()

// Check if empty

print("Empty : \(dict1.isEmpty)")

// Create an item with index of 1

dict1[1] = "Paul Smith"

// Create a dictionary with a string key

var cust: [String: String] = ["1": "Sally Marks", "2": "Paul Marks"]

// Size of dictionary

print("Size : \(cust.count)")

// Add an item

cust["3"] = "Doug Holmes"

// Change a value

cust["3"] = "Doug Marks"

// Get a value

if let name = cust["3"] {

print("Index 3 : \(name)")

}

// Remove a key value pair

cust["3"] = nil

// Iterate through a dictionary

for (key, value) in cust {

print("\(key) : \(value)")

}

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

// Tuples are finite group of values that are related

let height: Double = 6.25

let weight: Int = 175

// Create a tuple

let myData = (height, weight)

// Access values

print("Height : \(myData.0)")

// You can name values

let myData2 = (height: 6.25, weight: 175)

print("Weight : \(myData2.weight)")

// ----- OPTIONAL -----

// Optionals are used to indicate that there may

// not be a value. Everything that can have a

// value of nil should be declared optional

// Declare an optional

var politicalParty: String?

politicalParty = "Independent"

// Check for nil

if politicalParty != nil {

// Get the value (Forced Unwrapping)

let party = politicalParty!

print("Party : \(party)")

}

// Optional binding is used to check if an optional

// has a value

if let party = politicalParty {

print("Party : \(party)")

} else {

print("No Party")

}

// If nil use coalescing operator to assign a value

let party = politicalParty ?? "No Party"

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

// Define your parameter types

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

print("Sum : \(num1 + num2)")

}

getSum(num1: 5,num2: 6)

// Define your return type and you can define

// default values

func getSum2(num1: Int, num2: Int = 1) -> Int{

return num1 + num2

}

print("Sum : \(getSum2(num1: 8, num2: 6))")

// A variadic parameter allows for an unknown

// number of parameters

func getSum3(nums: Int...) -> Int{

var sum: Int = 0

for num in nums {

sum += num

}

return sum

}

print("Sum : \(getSum3(nums: 1,2,3,4,5))")

// Nested functions are only callable by the enclosing

// function

func doMath(num1: Double, num2: Double){

func mult() -> Double{

return num1 / num2

}

print("Mult : \(mult())")

}

doMath(num1: 5.0, num2: 6.0)

// Return multiple values

func twoMults(num: Int) -> (two: Int, three: Int){

let two: Int = num * 2

let three: Int = num * 3

return (two, three)

}

let mults = twoMults(num: 2)

print("2 Mults : \(mults.two), \(mults.three)")

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

// Closures are functions that don't require a name

// or function definition

// A closure that excepts and returns an Int

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

num in

return num * num

}

print("5 Quared : \(square(5))")

// Assign a closure to another variable

var squareCopy = square

print("5 Quared : \(squareCopy(5))")

// You can reference any values outside the closure

let numbers = [8,9,2,4,1,0,7]

// Create a function that returns a Bool stating

// if 1 value is greater then the other

let sortedNums = numbers.sorted(by: {

x, y in x < y

})

for i in sortedNums{

print(i)

}

// Square every item in an array with map

// map excepts a closure

let squaredNums = numbers.map {

(num: Int) -> String in

"\(num * num)"

}

print(squaredNums)

// Return a function

func funcMaker(val: Int) -> (Int) -> Int {

func addVals(num1: Int) -> Int{

return num1 + val

}

return addVals

}

let add4 = funcMaker(val: 4)

print("4 + 5 = \(add4(5))")

// Pass a function as a parameter

func doMath2(_ mathFunc: (Int, Int) -> Int, val: Int){

print("Sum : \(mathFunc(val, val))")

}

func addNums(a: Int, b: Int) -> Int {

return a + b

}

doMath2(addNums, val: 5)

// ----- FILTER -----

// Used to filter out values in an array

let nums2 = [1,2,3,4,5,6]

let evenNums = nums2.filter{

(num: Int) -> Bool in

return num % 2 == 0

}

print(evenNums)

// ----- REDUCE -----

// Reduces array values into one value

let sum2 = nums2.reduce(0) {

(x: Int, y: Int) -> Int in

return x + y

}

print(sum2)

// ----- ENUMERATIONS -----

// Define types with a limited number of cases

enum Emotion {

case joy

case anger

case fear

case disgust

case sad

}

var feeling = Emotion.joy

// change the value

feeling = .anger

// Check value

print("Angry : \(feeling == .anger)")

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

// Structs group related data together

struct Rectangle {

var height = 0.0

var length = 0.0

// You can include functions

func area() -> Double{

let area = height * length

return area

}

// Create a Rectangle

let myRect = Rectangle(height: 10.0, length: 5.0)

print("Area : \(myRect.height) * \(myRect.length) = \(myRect.area())")

// ----- 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(){

print("\(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(){

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

}

override func getInfo(){

// You can call a method in the superclass

super.getInfo()

print("and digs 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(animal: rover)

printGetInfo(animal: spot)

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

spot.name = "Doug"

print(spot.name)

// Testing overloaded methods

print("2 + 5 = \(spot.getSum(num1: 2,num2: 5))")

print("2.2 + 5.6 = \(spot.getSum(num1: 2.2,num2: 5.6))")

// Check the class type

print("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

print(fordF150.fly(distMiles: 10))

// ----- ERROR HANDLING -----

// Used to handle errors gracefully

// Define our error by defining a type of the Error protocol

enum DivisionError: Error{

case DivideByZero

}

// Define we want the error to get thrown from the function

func divide(num1: Float, num2: Float) throws -> Float {

guard num2 != 0.0 else {

throw DivisionError.DivideByZero

}

return num1/num2

}

// Wrap code that could trigger an error in a do catch block

// catch the error and handle it

do {

try divide(num1: 4, num2: 0)

} catch DivisionError.DivideByZero {

print("Can't Divide by Zero")

}

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

// Extensions add new functionality to existing classes, structs

// and other types

// Extend a Double to work with different distance units

// The Double by default is in meters and we can convert

// to other types by appending a dot syntax

extension Double {

var km: Double { return self * 1000.0 }

var m: Double { return self }

var ft: Double { return self * 3.28 }

var inch: Double { return self * 39.37}

// Add a method to Double for squares

mutating func square() -> Double {

let sqr = self * self

return sqr

}

// Convert 1 meter into inches

let oneMeter = 1.0.inch

print("One Meter is \(oneMeter) inches")

// Get the square

var randNum2: Double = 5

print("Square of 5 : \(randNum2.square())")

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