🎶 shake shake shake

Author: leah

.DS_Store

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+import Foundation
+
+
+// Hello!
+print("Hello Wisconsin!")
+
+
+// Variables
+var bae = "Calvin Harris"
+print("\(bae) is super cute.")
+bae = "Tom Hiddleston"
+print("\(bae) is much cuter.")
+
+// Constants
+let bff = "Karlie"
+print("My bff \(bff) is the best.")
+
+// Specifying a variable type
+var catCount: Int = 2
+print("I currently have \(catCount) cats.")
+
+
+// Emoji and characters
+let kitties = "🐱🐈😸😻"
+print(kitties)
+// 🐱🐈😸😻
+
+let title = "🎵 Shake it off"
+print("Title has \(title.characters.count) chars")
+// Title has 14 chars
+
+let 🐱 = "Meredith Gray"
+// Singletons: API.☁️.GET()
+
+
+// Optionals
+var currentHit: String? = nil
+currentHit = "Shake it off"
+
+print("Current hit is: \(currentHit)")
+// Current hit is: Optional("Shake it off")
+
+// Forced unwrapping
+print("Current hit is: \(currentHit!)")
+// Current hit is: Shake it off
+
+
+// Optional chaining
+func playHit(currentHit: String?) {
+    if let hit = currentHit {
+        print("🎶 \(hit) 🎶")
+    } else {
+        print("No hit right now.")
+    }
+}
+
+playHit(currentHit: nil)
+// No hit right now.
+
+playHit(currentHit: "Shake it off")
+// 🎶 Shake it off 🎶
+
+
+// Optional chaining
+func playHit(currentHit: String?, notes: String?) {
+    if let hit = currentHit, let notes = notes {
+        print("\(notes) \(hit) \(notes)")
+    }
+}
+
+playHit(currentHit: "Blank Space", notes: "🎵")
+// 🎵 Blank Space 🎵
+
+playHit(currentHit: "Bad Blood", notes: "☠️")
+// ☠️ Bad Blood ☠️
+
+
+// Optional chaining
+func playHitLouder(currentHit: String?) {
+    if let loudHit = currentHit?.uppercased() {
+        print("🔊🎶 \(loudHit) 🔊🎶")
+    }
+}
+
+playHitLouder(currentHit: "We are never ever getting back together")
+// 🔊🎶 WE ARE NEVER EVER GETTING BACK TOGETHER 🔊🎶
+
+
+// the _
+var cat: String? = "Olivia"
+if let _ = cat {
+    print("🐱 meow meow!")
+}
+
+
+// Array
+let awards: [String] = [
+    "Academy of Country Music",
+    "AMA",
+    "Academy of Country Music",
+    "Grammy",
+    "Billboard",
+    "MTV",
+    "Grammy",
+]
+// ... obviously not a complete list
+
+// Set
+let exes: Set<String> = [
+    "Joe Jonas",
+    "Taylor Lautner",
+    "Jake Gyllenhaal",
+    "John Mayer",
+    "Harry Styles",
+    "Calvin Harris"
+]
+// ... obviously not a complete set
+
+// Dictionary
+var squad: [String: String] = [
+    "Karlie Kloss": "model",
+    "Selena Gomez": "actress",
+    "Gigi Hadid": "model",
+    "Lena Dunham": "director",
+    "Hailee Steinfeld": "actress",
+    "Ed Sheeran": "musician"
+]
+// ... obviously not a complete dictionary
+
+
+// Loops
+for ex in exes {
+    // Lame in no particular order
+    print("My ex \(ex) is lame.")
+}
+/* My ex John Mayer is lame.
+ My ex Calvin Harris is lame.
+ My ex Joe Jonas is lame.
+ My ex Harry Styles is lame.
+ My ex Jake Gyllenhaal is lame.
+ My ex Taylor Lautner is lame. */
+
+// Looping over a dictionary
+for (bff, job) in squad {
+    print("\(bff) is a \(job).")
+}
+/* Lena Dunham is a director.
+ Ed Sheeran is a musician.
+ Karlie Kloss is a model.
+ Selena Gomez is a actress.
+ Gigi Hadid is a model.
+ Hailee Steinfeld is a actress. */
+
+// isEmpty
+if squad.isEmpty {
+    print("No way, my squad is never empty.")
+} else {
+    print("Party time! 🎉")
+}
+
+// Classes
+class MediaItem {
+    var name: String
+    
+    // Initializer
+    init(name: String) {
+        self.name = name
+    }
+    
+    // Deinitializer
+    deinit {
+        print("Deinitialize!")
+    }
+}
+
+
+// Subclasses
+class Song: MediaItem {
+    var albumName: String
+    
+    init(name: String, albumName: String) {
+        self.albumName = albumName
+        super.init(name: name)
+    }
+}
+
+class Movie: MediaItem {
+    var role: String
+    
+    init(name: String, role: String) {
+        self.role = role
+        super.init(name: name)
+    }
+}
+
+// MediaItem array
+let works: [MediaItem] = [
+    Song(name: "Fifteen", albumName: "Fearless"),
+    Movie(name: "Valentine's Day", role: "Felicia"),
+    Song(name: "Blank Space", albumName: "1989"),
+    Song(name: "Shake it Off", albumName: "1989")
+]
+// Type checking
+for work in works {
+    if work is Song {
+        print("\(work.name) is a song.")
+    } else if work is Movie {
+        print("\(work.name) is a movie.")
+    }
+}
+// Fifteen is a song.
+// Valentine's Day is a movie.
+// Blank Space is a song.
+// Shake it Off is a song.
+
+
+// Type casting
+for work in works {
+    if let song = work as? Song {
+        // Blank Space is on 1989
+        print("\(song.name) is on \(song.albumName)")
+    } else if let movie = work as? Movie {
+        // Felicia in Valentine's Day
+        print("\(movie.role) in \(movie.name)")
+    }
+}
+// Fifteen is on Fearless
+// Felicia in Valentine's Day
+// Blank Space is on 1989
+// Shake it Off is on 1989
+
+
+// Enumerations
+enum DanceStyle {
+    case ballet
+    case hiphop
+    case jazz
+    case cheerleader
+    case robot(name: String)
+}
+
+
+// Switch
+print("My dancing is...")
+
+var currentDancing = DanceStyle.ballet
+
+switch currentDancing {
+case DanceStyle.ballet:
+    print("graceful")
+case DanceStyle.hiphop:
+    print("dope")
+case DanceStyle.jazz:
+    print("cool")
+case DanceStyle.cheerleader:
+    print("rah rah")
+case DanceStyle.robot:
+    print("bleep bloop")
+}
+// My dancing is...
+// graceful
+
+// Switch...
+// break, variables, fallthrough, default
+currentDancing = DanceStyle.robot(name:"Dave")
+switch currentDancing {
+case DanceStyle.jazz:
+    print("boop boop boop.")
+case DanceStyle.ballet:
+break // do nothing
+case DanceStyle.robot(let name):
+    print("Hello, \(name).")
+case DanceStyle.cheerleader:
+    print("Won't you come over here baby, we can ")
+    fallthrough
+default:
+    print("shake shake shake.")
+}
+// Hello, Dave.
+
+
+// Guard
+func beachTime(bae: String?) {
+    guard let bae = bae else {
+        print("No pics needed.")
+        return
+    }
+    print("Take Instagram with my bae \(bae)!")
+}
+beachTime(bae: nil)
+// No pics needed.
+beachTime(bae: "Tom")
+// Take Instagram with my bae Tom!
+
+
+// Error handling
+enum Problem: ErrorProtocol {
+    case badBlood
+    case bulletHoles
+    case deepCut
+}
+
+func madLove() throws {
+    throw Problem.badBlood
+}
+
+do {
+    try madLove()
+} catch Problem.badBlood {
+    print("We've got bad blood!")
+} catch {
+    print("We've got a problem.")
+}
+
+
+// Ternary operator
+let grammyCount = 29
+let plural = grammyCount == 1 ? "" : "s"
+print("I won \(grammyCount) Grammy\(plural)!")
+// I won 29 Grammys!
+
+
+// Nil coalescing operator
+let defaultHairColor: String = "blond"
+
+var dyedHairColor: String? = nil
+var hairColor = dyedHairColor ?? defaultHairColor
+print("My hair is currently \(hairColor).")
+// My hair is currently blond.
+
+dyedHairColor = "bleach blond"
+hairColor = dyedHairColor ?? defaultHairColor
+print("My hair is currently \(hairColor).")
+// My hair is currently bleach blond.
+
+
+// Extensions
+extension Date {
+    // Before Taylor Swift
+    func isBTS() -> Bool {
+        let year = Calendar.current.component(.year, from: self)
+        return year < 1989
+    }
+}
+
+let now = Date()
+if now.isBTS() {
+    print("😭")
+} else {
+    print("😀")
+}
+// 😀
+

ShakeItOff.playground/Contents.swift

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='ios'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>