Concepts for Swift

Swift is a powerful and intuitive programming language developed by Apple for building iOS, macOS, watchOS, and tvOS applications. Introduced in 2014, Swift offers modern features like type inference, optionals, closures, and generics, which enhance developer productivity and code safety. Its syntax is concise and expressive, drawing inspiration from various programming languages such as Objective-C, Rust, and Python. Swift also provides strong support for functional programming paradigms, making it suitable for building robust, scalable, and high-performance applications. With its interoperability with Objective-C and extensive standard library, Swift has quickly become a preferred choice for iOS and macOS development, offering speed, safety, and ease of use to developers.

• Print Text

  print("Hello World!");

• Comments

  // one line comment
  
  /*
  multi 
  line 
  comment
  */

• Variables

  var carCount = 2;
  var name: String = "Joe";
  
  // constant variable
  let isPurple: Bool = true;

• Data Types

  var carCount: Int = 2;
  var age: UInt8 = 15;
  var seaLevel: Int16 = -10000;
  var usBudget: Int64 = 11000000000;
  var lightSpeed: UInt64 = 11799312874;
  var myGPA: Float = 3.45;
  var piValue: Double = 3.14159265;
  var isMale: Bool = true;
  var lastLetter: Character = "Z";
  var myName: String = "Joe";

• Math Op

  var carCount = 6;
  var truckCount = 3;
  
  var total = carCount + truckCount;
  print(total);
  
  var subtract = carCount - truckCount;
  print(subtract);
  
  var multiple = carCount * truckCount;
  print(multiple);
  
  var divisible = carCount / truckCount;
  print(divisible);
  
  // performs division and gets remainder which is 0
  var modulo = carCount % truckCount;
  print(modulo);

• Math Functions

  import Foundation
  
  let power = pow(3, 6);
  print(power);
  
  let root = sqrt(16);
  print(root);
  
  let floorVal = floor(3.14);
  print(floorVal);
  
  let ceilVal = ceil(4.3);
  print(ceilVal);
  
  let roundVal = round(3.4);
  print(roundVal);
  
  // random number from 0 to 100
  let ranNum = Int.random(in: 0..< 101)
  print(ranNum);

• If/Else

  let carCount = 6; 
  
  if carCount > 3 {
    print("More than three cars");
  } else if carCount == 3) {
    print("Equal to three cars");
  } else {
    print("Less than three cars");
  }

• Ternary

  let carCount = 3
  
  let result = (carCount > 2) ? "Yes" : "No";
  print(result);

• Switch

  let carCount = 3
  
  switch carCount {
    case 1:
      print("One car");
    case 2: 
      print("Two cars");
    case 3:
      print("Three cars");
    default:
      print("More than three");
  }

• Functions

  func handleCars(cars:Int, wheels:Int) -> Int {
    let total:Int = cars * wheels;
    return total;
  }
  
  let result:Int = handleCars(cars:3, wheels:4);
  print(result);

• Interpolation

  let name = "Joe";
  let car = "Mazda";
  let result = "\(name) drives a \(car)";
  print(result);

• Type Casting

  import Foundation
  
  func squareA(length:Int) -> String {
    let result = pow(Double(length), 2);
    return String(result);
  }
  
  let squareL = "4";
  let convertedVal:Int = Int(squareL) ?? 0;
  let area = squareA(length:convertedVal);
  print(area);

• Date and Time

  // epoch time
  let milliseconds =
    Date().timeIntervalSince1970 * 1000;
  print(milliseconds);
  
  let currentDate = Date();
  let calendar = Calendar.current;
  
  // current year
  let year = calendar.component(.year, from: currentDate);
  print(year);
  
  // current month
  let month = calendar.component(.month, from: currentDate);
  print(month);
  
  let day = calendar.component(.day, from: currentDate);
  
  // formatted date
  let formatted = "\(month)/\(day)/\(year)";
  print(formatted);

• Classes

  class Cars {
    var carList:Array<String> = []
    
    func addCar(car:String) {
      self.carList.append(car);
    }
  
    func removeFirst() {
      self.carList.removeFirst();
    }
  
    func getFirstVal()->String {
      if (self.carList.count > 0) {
        return self.carList[0];
      } 
      return "";
    }
  }
  
  let newList:Cars = Cars();
  newList.addCar(car: "Honda");
  newList.addCar(car: "Mazda");
  newList.addCar(car: "Toyota");
  newList.removeFirst();
  
  var firstCar:String =
    newList.getFirstVal();
  print(firstCar);

• Inheritance

  class User {
    var username:String;
    var password:String;
    
    init(username: String, password: String) {
      self.username = username
      self.password = password
    }
  }
  
  class Admin : User {
    var id:String;
  
    init(
      username: String, 
      password: String, 
      id:String) 
    {
      self.id = id
      super.init(
        username: username,
        password: password
      )
    }
    
    func fetchUsername() -> String {
      return self.username
    }
  
    func getAdminID() -> String  {
      return self.id
    }
  }
  
  var newAdmin = Admin(
    username: "alpha0",
    password: "pw1",
    id: "1FE"
  )
  
  print(newAdmin.fetchUsername())
  print(newAdmin.getAdminID())

• Method Overload

  class UserForm {
    var formA:String = "alpha";
    var formB:String = "beta";
    var formC:String = "gamma";
    var formD:String = "epsilon";
    
    func getForm(age: Int) -> String {
      if (age > 65) {
        return formA;
      }
      return formB;
    }
    
    func getForm(id: String) -> String {
      if (id == "1FE") {
          return formA;
      }
      return formC;
    }
    
    func getForm(
      isMilitary: Bool,
      isNasa: Bool
    ) -> String {
      if (isMilitary || isNasa) {
        return formD;
      }
      return formA;
    }
  }
  
  var form = UserForm();
  var myAge = 67;
  var myId = "1FE";
  var veteran = false;
  var nasa = true;
  
  var form1 =
    form.getForm(age: myAge);
  var form2 =
    form.getForm(id: myId);
  var form3 =
    form.getForm(
      isMilitary: veteran,
      isNasa: nasa
    );
    
  print(form1);
  print(form2);
  print(form3);

• Abstract Class

  // No Native Support or Implementation
  

• Static Class

  import Foundation
  
  struct Helper {
    static func CircleA(radius: Int) -> Double {
      return 3.14 * pow(Double(radius), 2.0);
    }
    static func SquareA(length: Int) -> Double {
      return pow(Double(length), 2.0);
    }
  }
  
  var circle = Helper.CircleA(radius: 3);
  print(circle);
      
  var square = Helper.SquareA(length: 4);
  print(square );

• Arrays/Lists

  var names = ["Joe", "Sam", "David"];
  names[1] = "Tom";
  
  // constant variable
  let name = names[1];
  let numItems = names.count;
  
  print(name);
  print(numItems);

• Array Methods

  var cars = ["Honda", "Mazda", "Toyota"];
  
  // adds element ot end of aray
  cars.append("Ford");
  print(cars);
  
  // check to see if element exists in arrayu
  print(cars.contains("Ford"));
  
  // removes first element
  var array1 = cars.dropFirst();
  print(array1);
  
  // removes second element
  var array2 = cars.dropLast();
  print(array2);
  
  // inserts element at index 1
  cars.insert("Ford", at: 1)
  print(cars);
  
  // removes element at index 1
  cars.remove(at:1);
  print(cars);
  

• Concatenation

  let carsListKr = ["Kia", "Hyundai", "Daewoo"];
  let carsListJp = ["Honda", "Mazda", "Toyota"];
  let combined = carsListKr + carsListJp;
  
  print(combined[1]);
  print(combined[4]);

• Sort Method

  var ages = [5, 3, 1, 6, 7, 4, 19]
  ages.sort()
  
  print(ages)

• Objects

  class User {
    var first:String;
    var last:String;
    var age:Int;
    var retired:Bool;
    var carBrands:Array<String>;
    
    init(
      first:String,
      last:String,
      age:Int,
      retired:Bool,
      carBrands:Array<String> 
    ) {
      self.first = first;
      self.last = last;
      self.age = age;
      self.retired = retired;
      self.carBrands = carBrands;
    }
    
    func fullName() -> String {
      return "\(first) \(last)";
    }
  }
  
  var user = User(
    first: "Joe",
    last: "Doe",
    age: 23,
    retired: false,
    carBrands: ["Mazda", "Toyota"]
  )
  
  print(user.first);
  print(user.carBrands[1]);
  print(user.fullName());

• Maps (Key/Value)

  var carMap = [String: String]()
  
  carMap["Joe"] = "Toyota"
  carMap["Bob"] = "Mazda"
  carMap["Tom"] = "Ford"
  
  var selected:String =
    carMap["Tom"] ?? ""
  
  print(selected);
  
  carMap.removeValue(forKey: "Tom")
  let keyCheck:Bool = carMap["Tom"] != nil
  print(keyCheck)

• Sets

  var cars = Set<String>();
  
  cars.insert("Mazda");
  cars.insert("Toyota");
  cars.insert("Honda");
  
  print(cars.contains("Honda")); 
  
  cars.remove("Honda");
  print(cars.contains("Honda")); 

• Stack

  var cars:Array<String> = [];
  cars.append("Mazda");
  cars.append("Toyota");
  cars.append("Honda");
  
  print(cars[cars.count - 1]);
  
  cars.removeLast();
  print(cars[cars.count - 1]);

• Queues

  var cars:Array<String> = [];
  cars.append("Mazda");
  cars.append("Toyota");
  cars.append("Honda");
  
  print(cars[0]);
  
  cars.removeFirst();
  print(cars[0]);

• Linked List

  class Node {
    var value: String;
    var next: Node? = nil;
    
    init(value:String) {
      self.value = value;
    }
  }
  
  class LinkedList {
    var head:Node? = nil;
    
    func add(Value:String) {
      let newNode = Node(value:Value)
      
      if (self.head == nil) {
        self.head = newNode;
      } else {
        var current:Node? = self.head;
        while(current?.next != nil) {
          current = current?.next;
        }
        current?.next = newNode;
      }
    }
    
    func returnHead() -> String {
      return self.head?.value ?? "";
    }
    
    func traverse() {
      var current:Node? = self.head;
       
      while(current != nil) {
        print(current?.value ?? "");
        current = current?.next;
      }
    }
  }
  
  var carList = LinkedList();
  carList.add(Value: "Mazda");
  carList.add(Value: "Toyota");
  carList.add(Value: "Honda");
  
  print(carList.returnHead());
  carList.traverse();

• Graphs

  class Graph {
    var graphMap = [String: Array<String>]();
    
    func addNode(val:String) {
      graphMap[val] = [];
    }
    
    func addVertices(node1:String, node2:String) {
      if (graphMap[node1] == nil) {
        graphMap[node1] = [];
      }
          
      if (graphMap[node2]  == nil) {
        graphMap[node2] = [];
      }
      graphMap[node1]?.append(node2);
      graphMap[node2]?.append(node1);
    }
    
    func breadthTraverse(start:String) {
      var queue = [start];
      var visited = [String: Bool]();
      visited[start] = true;
      
      while(queue.count > 0) {
        let currentVal = queue[0];
        print(currentVal);
        queue.removeFirst();
        
        let tempArr = graphMap[currentVal] ?? [];
        
        for tempVal in tempArr {
          if visited[tempVal] == nil {
            queue.append(tempVal);
            visited[tempVal] = true;
          }
        }
      }
    }
    
    func depthTraverse(start:String) {
      var stack = [start];
      var visited = [String: Bool]();
      visited[start] = true;
      
      while(stack.count > 0) {
        let currentVal = stack[stack.count - 1];
        print(currentVal);
        stack.removeLast();
        
        let tempArr = graphMap[currentVal] ?? [];
        
        for tempVal in tempArr {
          if visited[tempVal] == nil  {
            stack.append(tempVal);
            visited[tempVal] = true;
          }
        }
      }
    }
  }
  
  var newGraph = Graph();
  newGraph.addNode(val:"a");
  newGraph.addVertices(node1:"a", node2:"b");
  newGraph.addVertices(node1:"a", node2:"c");
  newGraph.addVertices(node1:"b", node2:"d");
  newGraph.addVertices(node1:"b", node2:"e");
  newGraph.addVertices(node1:"d", node2:"f");
  newGraph.addVertices(node1:"d", node2:"g");
  newGraph.addVertices(node1:"d", node2:"h");
  newGraph.addVertices(node1:"e", node2:"i");
  newGraph.addVertices(node1:"e", node2:"j");
  newGraph.breadthTraverse(start:"a");
  newGraph.depthTraverse(start:"a");

• For Loops

  var names = ["Joe", "Alex", "Bob"];
  
  for name in names {
      print(name);
  }

• While Loops

  var carList = ["Mazda", "Toyota", "Honda"];
  
  while(carList.count > 0) {
    print(carList[0]);
    carList.removeFirst();
  }
  
  print(carList.count)

• Loop Breaks

  var cars = ["Toyota", "Honda", "Mazda"];
  
  for (i, car) in cars.enumerated() {
    if (car == "Honda") {
      print("Found at index \(i)")
      break;
    }
    print("Visited index \(i)")
  }

• Recursion

  func getSum(arr: Array<Int>) -> Int {
    var copy = arr;
    if copy.count == 0 {
        return 0;
    }
    
    let val = copy[0];
    copy.removeFirst();
    return val + getSum(arr:copy);
  }
  
  var testArr = [1, 2, 4, 5];
  var sum = getSum(arr: testArr);
  print(sum)

• Regex Words

  var phrase = "I am legend";
  var pattern = try Regex("\\w+");
  
  if let result = phrase.firstMatch(of: pattern) {
    print(result.0);
  }

• Regex Numbers

  var phrase = "I am 23";
  var pattern = try Regex("\\d+");
  
  if let result = phrase.firstMatch(of: pattern) {
    print(result.0);
  }

• Regex Test

  let phrase = "Bob Lee";
  let pattern = "Lee";
  var result: Bool;
  
  if phrase.contains(pattern) {
    result = true;
  } else {
    result = false;
  }
  
  print(result);
  

• Regex Characters

  var phrase = "##I am legend##";
  var pattern = try Regex("#+\\w+");
  
  if let result = phrase.firstMatch(of: pattern) {
    print(result.0);
  }