Added source code from other repo.

01-beginning-swift-optionals.playground/Contents.swift

@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) 2020 Razeware LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * Notwithstanding the foregoing, you may not use, copy, modify, merge, publish,
+ * distribute, sublicense, create a derivative work, and/or sell copies of the
+ * Software in any work that is designed, intended, or marketed for pedagogical or
+ * instructional purposes related to programming, coding, application development,
+ * or information technology.  Permission for such use, copying, modification,
+ * merger, publication, distribution, sublicensing, creation of derivative works,
+ * or sale is expressly withheld.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+// Creates an optional Int, defaults to nil
+var foundIndex: Int?
+
+// You can set an optional to a value...
+foundIndex = 42
+
+// Or you can set it to nil!
+foundIndex = nil
+
+// Test data
+let array = Array(0...100)
+
+// Comment this if you want the program to crash
+foundIndex = 42
+
+// Force unwrapping
+// Avoid this; it will crash if foundIndex is nil!
+let unwrappedIndex: Int = foundIndex!
+print(array[unwrappedIndex])
+
+// Safely unwrap with if let
+if let unwrappedIndex = foundIndex {
+  // Only executes this line if foundIndex isn't nil
+  print(array[unwrappedIndex])
+}
+
+// You can also shadow the Int? with an Int w/ the same name
+if let foundIndex = foundIndex {
+  print(array[foundIndex])
+}
+
+// Use guard let to exit early from a func if there is no value to unwrap
+func printElement() {
+  guard let foundIndex = foundIndex else {
+    return
+  }
+  // Only executes this line if foundIndex isn't nil
+  print(array[foundIndex])
+}
+
+// Safely unwrap in a functional way with map
+foundIndex.map { print($0) }
+
+// Test data
+struct Address {
+  var phoneNumber: String?
+}
+struct Person {
+  var address: Address?
+}
+var person: Person?
+
+// Comment this if you want the program to crash
+person = Person(address: Address(phoneNumber: "123-123-1234"))
+
+// Use optional chaining to safely test nested optionals
+if let number = person?.address?.phoneNumber {
+  print(number)
+}
+
+// Avoid this; it will crash if any of these optionals are nil!
+if let number = person!.address!.phoneNumber {
+  print(number)
+}
+
+person = Person(address: nil)
+
+// Use the nil coalescing operator for a fallback value
+let number = person?.address?.phoneNumber ?? "867-5309"
+print(number)
+
+// Test data
+struct Door {
+  var doorName: String
+  public var description: String { return doorName }
+}
+let frontDoor: Door? = Door(doorName: "Front")
+let sideDoor: Door? = Door(doorName: "Side")
+let backDoor: Door? = nil
+
+// Returns first non-nil element (or nil if all are nil)
+let door = frontDoor ?? sideDoor ?? backDoor
+if let door = door {
+  print(door)
+}
+
+let anotherDoor = backDoor ?? Door(doorName: "Trap")
+

01-beginning-swift-optionals.playground/contents.xcplayground

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>

03-beginning-swift-control-flow.playground/Contents.swift

@@ -73,15 +73,43 @@ for _ in 1...3 {
 
 print("\nWhere Clause")
 
-for i in 1...10 where i % 2 == 1 {
+for i in 1...10 where i.isMultiple(of: 2) {
   print("\(i) is an odd number.")
 }
 
 print("\nIterating Over Arrays")
 
 let daysOfTheWeek = ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]
 for day in daysOfTheWeek {
-  print(day, terminator: " ")
+  print(day)
+}
+
+// More functional alternative
+daysOfTheWeek.forEach { print($0) }
+
+// Alternative ways to iterate an array, from very manual -> algorithmic
+for i in 0 ..< daysOfTheWeek.count {
+  print("Day \(i): \(daysOfTheWeek[i])")
+}
+
+for i in daysOfTheWeek.indices {
+  print("Day \(i): \(daysOfTheWeek[i])")
+}
+
+for day in daysOfTheWeek {
+  if let i = daysOfTheWeek.lastIndex(of: day) {
+    print("Day \(i): \(day)")
+  }
+}
+
+i = 0
+for day in daysOfTheWeek {
+  print("Day \(i): \(day)")
+  i += 1
+}
+
+for (i, day) in daysOfTheWeek.enumerated() {
+  print("Day \(i): \(day)")
 }
 
 print("\nIterating Over Dictionaries")

03-beginning-swift-control-flow.playground/contents.xcplayground

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<playground version='5.0' target-platform='ios' executeOnSourceChanges='true'>
+<playground version='5.0' target-platform='ios' buildActiveScheme='true'>
     <timeline fileName='timeline.xctimeline'/>
 </playground>