swift-programming part 1

1

Introduction of Swift

Presenter: Waseem Ahmad, Mindfire SolutionsDate: 28/10/2014

What you will learn

Presenter: Waseem Ahmad, Mindfire Solutions

What is Swift?VariableConstants Type InferenceType AliasesString/Character InterpolationArray and DictionaryLoopsOptionals, Unwrapping an OptionalFunctionsTuplesClassesPropertiesClosuresQ & A

What is Swift ?

• Swift is Apple’s modern, type-safe language for Cocoa development that builds on the best of C and Objective-C

• Safe• Modern• Power


Variables

var variableName : String = “Swift”var version: Double = 1.0var day: Int = 28var isAnimated: Bool = true


Constants & Variables

let variableName: String = “Swift”var version: Double = 1.0var day: Int = 28var isAnimated: Bool = true

Pretty clear which is constant and mutable, it’s define safe code in multithreaded environment. Make code more clear and readable.


Constants & Variables

let variableName: String = “Swift”var version: Double = 1.0let day: Int = 28let isAnimated: Bool = true


Type Inference

let variableName = “Swift” // As Stringvar version = 1.0 // As Double/Floatlet day = 28 // As Intlet isAnimated = true // As Boolean

Code safe, these are valuable & constant explicitly type.


Type Aliases

An alternative name for an existing type.

typealias AudioSample = UInt16

var maxAmplitudeFound = AudioSample.min


Unicode Names

let variableName = “Swift” // As Stringvar version = 1.0 // As Double/Floatlet day = 28 // As Intlet isAnimated = true // As Booleanlet π = 3.1415927let � = "emoji"�


String

var studentName: String = “Waseem” var studentName = “Waseem” // Inferred to be of type string


String

var studentName: String = “Waseem” var studentName = “Waseem” // Inferred to be of type string

var documentsPath = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as StringdocumentsPath = documentsPath.stringByAppendingString(subpath)


Character

let studentName = “Waseem"

for character in studentName { println(character)}

Waseem


Complex String

var name = “Waseem”var coins = 100

Congratulations, Waseem won 100 coins.


String Interpolation

var name = “Waseem”var coins = 100

Congratulations, Waseem won 100 coins.

let message = “Congratulations, \(name) won \(coins)”.


String Mutability

var variableString = "Mindfire"


String Mutability

var variableString = “Mindfire"variableString += " Solutions”

// variableString is now “Mindfire Solutions"


String Mutability

var variableString = “Mindfire"variableString += " Solutions”

// variableString is now “Mindfire Solutions"

let constantString = “Mindfire"constantString += " Solutions”

// error - constantString cannot be changed


Collection Type (Array & Dictionary)


Array and Dictionary Literalsvar names = [“John”, “Bob”, "Brian", "Jack"]


Array and Dictionary Literalsvar names = [“John”, “Bob”, "Brian", “Jack"]var numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]


Difference Between NSArray & NSDictionary- It could work with any type (String, Int etc)- Collection are typed collection


Typed Collectionvar names = [“John”, “Bob”, "Brian", “Jack”, 123]var names = [“John”, “Bob”, "Brian", “Jack”, function()]


Typed Collectionvar names: String[] = [“John”, “Bob”, "Brian", “Jack”]


Typed Collectionvar names = [“John”, “Bob”, "Brian", “Jack”]

// An array of String Values

var numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]// An Dictionary With String Keys and Int Values

Typed collection made your code safe, you well know what you are retrieving and adding.


Loopwhile !isTrue { print(“hello”)}

for var i = 1; i <= 13; ++i { print(“hello”)}


For-In: Strings and Characterslet studentName = “Waseem"

for character in studentName { println(character)}

Waseem

Swift Power, we can use character & emoji in similar way.


For-In: Rangesfor number in 1...5 { // Clause Range println("\(number) times 4 is \(number * 4)")}

1 times 4 is 42 times 4 is 83 times 4 is 124 times 4 is 165 times 4 is 20


For-In: Rangesfor number in 0..5 { // half clause range println("\(number) times 4 is \(number * 4)")}

0 times 4 is 01 times 4 is 42 times 4 is 83 times 4 is 124 times 4 is 16


For-In: Arrayvar names = [“John”, “Bob”, "Brian", "Jack"]

for name in names { println("Hello \(name)")}


For-In: Dictionarieslet numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]!for (animalName, legCount) in numberOfLegs { println("\(animalName)s have \(legCount) legs")}

ants have 6 legs

Power of swift extracting key and value in single loop, grouping of value is a power full feature of swift i.e Tuples


Modification in Arrayvar shoppingList = ["Eggs", "Milk"]println(shoppingList[0])


Modification in Arrayvar shoppingList = ["Eggs", "Milk"]println(shoppingList[0])

shoppingList += "Flour"shoppingList += ["Cheese", "Butter", "Chocolate Spread"]


Modification in Arrayvar shoppingList = ["Eggs", "Milk"]

shoppingList += "Flour"shoppingList += ["Cheese", "Butter", "Chocolate Spread”]shoppingList[0] = "Six eggs"


Modification in Arrayvar shoppingList = ["Eggs", "Milk"]

shoppingList += "Flour"shoppingList += ["Cheese", "Butter", "Chocolate Spread”]shoppingList[0] = "Six eggs”

["Six eggs", "Milk", "Flour", "Cheese", "Butter","Chocolate Spread"]

shoppingList[3...5] = ["Bananas", “Apples"]

["Six eggs", "Milk", "Flour", "Bananas", “Apples"]


Modification in Dictionaryvar numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]

numberOfLegs["spider"] = 273


Modification in Dictionaryvar numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]



What happen if we try to fetch a value that doesn’t have in array and dictionary?

let lionLegCount = numberOfLegs[“lion”] // Nothing at all :)


Optionalvar numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]

let lionLegCount: Int? = numberOfLegs["lion"]


Optionalvar numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]

let lionLegCount: Int? = numberOfLegs[“lion"]

if lionLegCount == nil { println("Lion wasn't found")} else { let legCount = lionLegCount! // unwrapping of optional value println("An lion has \(legCount) legs")}


Optionalif numberOfLegs { let legCount = numberOfLegs! println("An Lion has \(legCount) legs")}


Unwrapping an Optionalif let legCount = numberOfLegs { println("An Lion has \(legCount) legs")}

Note:- Braces are required with If :)


Switchswitch legCount { case 0:

println("It slithers and slides around”)

case 1: println("It hops")

default: println("It walks")}


Switchswitch sender { case executeButton:

println("You tapped the Execute button")

case firstNameTextField: println("You tapped the First Name text field")

default: println("You tapped some other object")}



println("It slithers and slides around")!

case 1, 3, 5, 7, 9, 11, 13: println("It limps")

case 2, 4, 6, 8, 10, 12, 14: println("It walks")}

// error: switch must be exhaustive




case 1, 3, 5, 7, 9, 11, 13: println("It limps")

case 2, 4, 6, 8, 10, 12, 14: println("It walks”)



Matching Value Rangesswitch legCount { case 0:


case 1…8: println("It has few lags")



Functionsfunc sayHello() { println("Hello!")}


Functions with Parametersfunc sayHello(name: String) { println("Hello \(name)!")}


Default Parameter Valuesfunc sayHello(name: String = "World") { println("Hello \(name)!")}

sayHello() // Hello WorldsayHello(“Team”) // Hello Team


Returning Valuesfunc greetingMsg(name: String = "World") -> String { return "Hello " + name}

let greeting = greetingMsg()


Returning Multiple Valuesfunc getUsernInfo() -> (Int, String) { return (25, “John”)}


Tuples-Grouping a values -Value could be any type

(3.79, 3.99, 4.19) // (Double, Double, Double)(404, "Not found")(2, "banana", 0.72)

-Tuple is not an replacement of structure but this is best when needs to return multiple values like from function

func getUsernInfo() -> (Int, String) { return (25, “John”)}


Decomposing of Tuplesfunc getUsernInfo() -> (Int, String) { return (25, “John”)}

let (age, name) = getUsernInfo()

println(“This is \(name) and my age is \(age)")


Decomposing of Tuplesfunc getUsernInfo() -> (Int, String) { return (25, “John”)}

let (age, name) = getUsernInfo()

let (age: Int, name: String) = getUsernInfo()

println(“This is \(name) and my age is \(age)")

If you only need some of the tuple’s values, ignore parts of the tuple with an underscore (_) when you decompose the tuple:

let (age, _) = getUsernInfo()


Named Values in a Tuplefunc getUsernInfo() -> (age: Int, name: String) { return (25, “John”)}

let userInfo = getUsernInfo()

println(“This is \(userInfo.name) and my age is \(userInfo.age)”)


Classesclass Student { // properties

// methods // initializers}

class Student: NSObject { // no need to derive a class with base as NSObject}

We can create a subclass and inherited

class Medical: Student {}


Propertiesclass Student { var rollNo = 1

var name: String?

// methods // initializers}

The big difference between objective c and swift is “no difference between Instance variable and priorities”.

Here rollNo we can say as stored properties.


Computed Propertiesclass Student { var rollNo = 1

var name: String?

var description: String { get {

return “Hi this \(name!) and my roll number is \(rollNo)“}

} }


Computed Properties (RW)class Student { var rollNo = 1

var name: String?

var description: String { get {

return “Hi this \(name!) and my roll number is \(rollNo)“}set {}

} }


Computed Properties (Read)class Student { var rollNo = 1

var name: String?

var description: String { return “Hi this \(name!) and my roll number is \(rollNo)“}

}


Initializer Class Syntaxclass Student { var rollNo = 1var name: String?

var description: String { return “Hi this \(name!) and my roll number is \(rollNo)“} }

let studentObj = Student()println(studentObj.description)

- Automatic memory allocation-No need to write type as Swift support Type Inferencelet studentObj : Student = Student()


Initializer Class Syntaxclass Student { var rollNo = 1

var name: String?

init() { // constructorstring = “Waseem”

}

var description: String { return “Hi this \(name!) and my roll number is \(rollNo)“}

}


Overriding a Propertyclass Medical: Student { init() { super.init() } override var description: String { // Safe return super.description + ", student of Medical" }}


Property Observersclass Loan: Bank { override var intrest: Double {

willSet { // newValue is available here

if intrest > 10.0 {// calculate // trigger

}}

}didSet {

// oldValue is available here}

} }


Methodsclass Student { var rollNo = 1

var name: String?

func studentName(nameStr: String) { name = nameStr

}}


Class Methodsclass func isFileExistAtPath(filePath: NSString) -> Bool {

let filemanager = NSFileManager.defaultManager()return filemanager.fileExistsAtPath(filePath)

}


Class De-initialisationclass Student { var rollNo = 1

var name: String?

init() { // constructorfileOpen() //

}

deinit { // constructorcloseFile() //

}}


iPhone App to Advertise Real Estate

Case Study

www.mindfiresolutions.com

http://bit.ly/17uzp5E

http://bit.ly/17uzp5E

Next Seminar: Swift in depthClosuresStructuresEnumExtensionsMemory ManagementOptional ChainingGeneric type


References- Apple WWDC 2014- Apple Inc. “The Swift Programming Language.” iBooks.



Question and Answer

Thank you


swift-programming part 1

Software

waseem ahmad

waseem var studentname

mindfire solutionswhat

mindfire solutionspresenter

mindfire solutions date

solutions variablestring

var isanimated

var day