The document contains code snippets demonstrating various Swift programming concepts including variables, constants, types, optionals, functions, classes, structs, enums, and more. Key concepts demonstrated include variable and constant declaration with types, optional binding, functions with parameters and return values, classes and structs with properties and methods, tuples, and enums with associated values and raw values.

8. //
var name = "Suyeol Jeon"
//
let birthyear = 1995

9. //
name = " "
//
birthyear = 2000
! Cannot assign to value: 'birthyear' is a 'let' constant

10. var name: String = "Suyeol Jeon"
let birthyear: Int = 1995
var height: Float = 180.1

11. var name: String = "Suyeol Jeon"
let birthyear: Int = 1995
var height: Float = 180.1
"ABC" String
123 Int

12. [String] [String: String]
let languages = [
"Swift",
"Objective-C",
"Python",
]
var capitals = [
" ": " ",
" ": " ",
" ": " ",
]

13. if for switch

14. for _ in 0..<10 {
print("Hello!")
}
• for i in 0..<10
i
•

15. switch age {
case 8..<14:
student = " "
case 14..<17:
student = " "
case 17..<20:
student = " "
default:
student = " "
}

17. " "

18. " "
"" // ?

19. " "
"" // ?

20. " "
nil //

21. 123
0 //
nil //

22. var name: String = " "
name = nil
! Nil cannot be assigned to type 'String'
String nil

23. var name: String? = " "
name = nil
? String

24. nil
var email: String?
print(email) // nil
email = "devxoul@gmail.com"
print(email) // Optional("dev...com")

25. String? String
let optional: String? = "Hello"
let required: String = optional
! Value of optional type 'String?' not unwrapped; did you
mean to use '!' or '?'?

26. String? String
String String?

27. "A" 10
nil

29. let optionalName: String? = " "
if let name = optionalName {
print(name)
}

30. let optionalName: String? = " "
if let name = optionalName {
print(name)
}

31. let optionalName: String? = " "
if let name = optionalName {
print(name)
}

32. let optionalName: String? = " "
if let name = optionalName {
print(name)
}
" "

33. let optionalName: String? = " "
if let name = optionalName {
print(name)
}
let name: String = " "

34. let optionalName: String? = " "
if let name = optionalName {
print(name) //
}

35. let optionalName: String? = " "
if let name = optionalName {
print(name) //
}

36. let optionalName: String?
if let name = optionalName {
print(name)
}

37. let optionalName: String?
if let name = optionalName {
print(name)
}

38. let optionalName: String?
if let name = optionalName {
print(name)
}
nil

39. let optionalName: String?
if let name = optionalName {
print(name)
}

40. if let name = optionalName,
let age = optionalAge {
print(name, age)
}

41. if let age = optionalAge
where age >= 20 {
print(age)
}
where

43. if let arr = optionalArray {
print(arr.isEmpty)
} else {
print(false)
}

44. print(optionalArray?.isEmpty == true)

45. print(optionalArray?.isEmpty == true)

46. print(optionalArray?.isEmpty == true)

47. print(optionalArray?.isEmpty == true)

48. print(optionalArray?.isEmpty == true)

49. print(optionalArray?.isEmpty == true)

50. let optionalName: String? = " "
print(optionalName) // Optional(" ")
print(optionalName!) //

52. var email: String! = " "
print(email) //
nil

53. func hello(name: String, time: Int) -> String {
var string = ""
for _ in 0..<time {
string += "(name) !n"
}
return string
}

54. func hello(name: String, time: Int) -> String {
var string = ""
for _ in 0..<time {
string += "(name) !n"
}
return string
}
hello(" ", time: 3)

55. func hello(name: String, time: Int) -> String {
var string = ""
for _ in 0..<time {
string += "(name) !n"
}
return string
}
hello(" ", time: 3)

56. func hello(name: String, numberOfTimes time: Int) -> Void {
print(time)
}
hello(" ", numberOfTimes: 3)

57. func hello(name: String, numberOfTimes time: Int) -> Void {
print(time)
}
hello(" ", numberOfTimes: 3)

58. func hello(withName name: String,
numberOfTimes time: Int) -> Void {
print(time)
}
hello(withName: " ", numberOfTimes: 3)

59. func hello(withName name: String,
numberOfTimes time: Int) -> Void {
print(time)
}
hello(withName: " ", numberOfTimes: 3)

60. func hello(name: String, _ time: Int) -> Void {
print(time)
}
hello(" ", 3)

61. func hello(name: String, time: Int = 1) -> Void {
print(time)
}
hello(" ")

62. func sum(numbers: Int...) -> Int {
var sum = 0
for number in numbers {
sum += number
}
return sum
}
sum(1, 2)
sum(3, 4, 5)

63. func hello(name: String, time: Int) {
func message(name: String) {
return "(name) !"
}
for _ in 0..<time {
print message(name)
}
}

64. func helloGenerator(message: String) -> String -> String {
func hello(name: String) -> String {
return name + message
}
return hello
}
let hello = helloGenerator(" !")
hello(" ")

65. func helloGenerator(message: String) -> String -> String {
func hello(name: String) -> String {
return name + message
}
return hello
}
let hello = helloGenerator(" !")
hello(" ")

66. func helloGenerator(message: String) -> (String, String) -> String {
func hello(firstName: String, lastName: String) -> String {
return lastName + firstName + message
}
return hello
}
let hello = helloGenerator(" !")
hello(" ", " ")

67. func helloGenerator(message: String) -> (String, String) -> String {
func hello(firstName: String, lastName: String) -> String {
return lastName + firstName + message
}
return hello
}
let hello = helloGenerator(" !")
hello(" ", " ")

68. func helloGenerator(message: String) -> (String, String) -> String {
return { (firstName: String, lastName: String) -> String in
return lastName + firstName + message
}
}
func helloGenerator(message: String) -> (String, String) -> String {
func hello(firstName: String, lastName: String) -> String {
return lastName + firstName + message
}
return hello
}

69. func helloGenerator(message: String) -> (String, String) -> String {
return { (firstName: String, lastName: String) -> String in
return lastName + firstName + message
}
}

70. func helloGenerator(message: String) -> (String, String) -> String {
return { (firstName: String, lastName: String) -> String in
return lastName + firstName + message
}
}

71. func helloGenerator(message: String) -> (String, String) -> String {
return { firstName , lastName in
return lastName + firstName + message
}
}

72. func helloGenerator(message: String) -> (String, String) -> String {
return { firstName, lastName in
return lastName + firstName + message
}
}

73. func helloGenerator(message: String) -> (String, String) -> String {
return { firstName, lastName in
return lastName + firstName + message
}
}

74. func helloGenerator(message: String) -> (String, String) -> String {
return {
return $1 + $0 + message
}
}

75. func helloGenerator(message: String) -> (String, String) -> String {
return {
return $1 + $0 + message
}
}

76. func helloGenerator(message: String) -> (String, String) -> String {
return { $1 + $0 + message }
}
func helloGenerator(message: String) -> (String, String) -> String {
return {
return $1 + $0 + message
}
}

77. let hello: (String, String) -> String = { $1 + $0 + " !" }
hello(" ", " ")

78. let hello: ((String, String) -> String)? = nil
hello?(" ", " ")

79. func manipulateNumber(number: Int,
usingBlock block: Int -> Int) -> Int {
return block(number)
}
manipulateNumber(10, usingBlock: { (number: Int) -> Int in
return number * 2
})

80. manipulateNumber(10, usingBlock: {
$0 * 2
})
manipulateNumber(10, usingBlock: { (number: Int) -> Int in
return number * 2
})
manipulateNumber(10) {
$0 * 2
}

81. let numbers = [1, 3, 2, 6, 7, 5, 8, 4]
let sortedNumbers = numbers.sort { $0 < $1 }
print(sortedNumbers) // [1, 2, 3, 4, 5, 6, 7, 8]
let evens = numbers.filter { $0 % 2 == 0 }
print(evens) // [2, 6, 8, 4]

82. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

83. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

84. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

85. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

86. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

87. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

88. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

89. let arr1 = [1, 3, 6, 2, 7, 9]
let arr2 = arr1.map { $0 * 2 }
// [2, 6, 12, 4, 14, 18]

90. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28

91. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
0 1+

92. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
0 1+ = 1

93. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
1 3
0 1+ = 1
+

94. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
1 3
0 1+ = 1
+ = 4

95. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
1 3
0 1+ = 1
+ = 4
4 6+

96. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
1 3
0 1+ = 1
+ = 4
4 6+ = 10

97. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: { $0 + $1 }) // 28
1 3
0 1+ = 1
+ = 4
4 6+ = 10

98. let arr1 = [1, 3, 6, 2, 7, 9]
arr1.reduce(0, combine: +) // 28

99. class Dog {
var name: String?
var age: Int?
func simpleDescription() -> String {
return "" (self.name)"
}
}
struct Coffee {
var name: String?
var size: String?
func simpleDescription() -> String {
return "☕ (self.name)"
}
}

101. class Dog {
var name: String?
var age: Int?
init() {
self.age = 0 //
}
}

102. class Dog {
var name: String //
var age: Int?
init() {
self.age = 0
}
} ! Return from initializer without initializing all stored properties

103. class Dog {
var name: String = " "
var age: Int?
init() {
self.age = 0
}
}

104. class Dog: Animal {
var name: String?
var age: Int
override init() {
self.age = 0 //
super.init() //
// `self`
print(self.simpleDescription())
}
func simpleDescription() -> String {
return "" (self.name)"
}
}

106. struct Hex {
var decimal: Int?
}

107. struct Hex {
var hexString: String? {
get {
if let decimal = self.decimal {
return String(decimal, radix: 16)
} else {
return nil
}
}
set {
if let newValue = newValue {
self.decimal = Int(newValue, radix: 16)
} else {
self.decimal = nil
}
}
}
}

108. struct Hex {
var hexCode: String? {
if let hex = self.hexString {
return "0x" + hex
}
return nil
}
}

109. struct Hex {
var decimal: Int? {
willSet {
print("(self.decimal) (newValue) .")
}
didSet {
print("(oldValue) (self.decimal) .")
}
}
}

110. var coffeeInfo = (" ", 5100)
coffeeInfo // (String, Int)
coffeeInfo.0 //
coffeeInfo.1 // 5100
coffeeInfo.1 = 5100

111. var namedCoffeeInfo = (coffee: " ",
price: 5100)
namedCoffeeInfo.coffee //
namedCoffeeInfo.price // 5100
namedCoffeeInfo.price = 5100

112. let (coffee, price) = (" ", 5100)
coffee //
price // 5100
let (_, latteSize, lattePrice) = (" ",
"Venti", 5600)
latteSize // Venti
lattePrice // 5600

113. func coffeeInfoForName(name: String) -> (name: String, price: Int)? {
let coffeeInfoList: [(name: String, price: Int)] = [
(" ", 5100),
(" ", 5600),
]
for coffeeInfo in coffeeInfoList {
if coffeeInfo.name == name {
return coffeeInfo
}
}
return nil
}
coffeeInfoForName(" ")?.price // 5100
coffeeInfoForName(" ")?.price // nil

114. enum Month: Int {
case January = 1
case February
case March
case April
case May
case June
case July
case August
case September
case October
case November
case December
}

115. enum Month: Int {
case ...
func simpleDescription() -> String {
switch self {
case .January:
return "1 "
case .February:
return "2 "
case ...
return "..."
case .December:
return "12 "
}
}
}

116. let december = Month.December
print(december.simpleDescription()) // 12
print(december.rawValue) // 12

117. let october = Month(rawValue: 10)
print(october) // Optional(Month.October)

118. enum IssueState: String {
case Open = "open"
case Closed = "closed"
}
let state = IssueState(rawValue: "open")
print(state) // Optional(IssueState.Open)

119. enum Spoon {
case Dirt
case Bronze
case Silver
case Gold
}

120. enum Spoon {
case Dirt
case Bronze
case Silver
case Gold
}
let spoon: Spoon = .Gold
func doSomething(spoon: Spoon) {
// ...
}
doSomething(.Silver)

121. enum Error {
case InvalidParameter(String, String)
case Timeout
}
let error = Error.InvalidParameter(
"email",
" ."
)

122. if case .InvalidParameter(let field, let message) = error {
print(field) // email
print(message) // .
}

123. switch error {
case .InvalidParameter(let field, let message):
print(field) // email
print(message) // .
default:
break
}

124. public enum Optional<Wrapped> {
case None
case Some(Wrapped)
}

125. let age: Int? = 20
switch age {
case .None: // `nil`
print(" .")
case .Some(let x) where x < 20:
print(" ")
case .Some(let x) where x < 65:
print(" ")
default:
print(" ")
}

126. /// .
protocol Sendable {
var from: String? { get }
var to: String { get }
func send()
}

127. struct Mail: Sendable {
var from: String?
var to: String
func send() {
print("Send a mail from (self.from) to (self.to)")
}
}

128. func sendAnything<T: Sendable>(sendable: T) {
sendable.send()
}

129. protocol Messagable {
var message: String? { get }
}
protocol Sendable: Messagable {
// ...
}

130. let anyNumber: Any = 10
let anyString: Any = "Hi"
let anyInstance: AnyObject = Dog()

131. extension String {
var length: Int {
return self.characters.count
}
func reverse() -> String {
return self.characters.reverse()
.map { String($0) }
.joinWithSeparator("")
}
}

133. protocol Sendable {
var from: String? { get }
var to: String { get }
func send()
}
extension Sendable {
func debug() {
print("(self.from) -> (self.to)")
}
}