Created
January 15, 2019 06:28
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| // Swift safety | |
| /// Type safety | |
| let i: UInt8 = 1 | |
| let x: Int = 4 | |
| // Error | |
| // let result = i*x | |
| func superPrint(string: String) { | |
| for _ in [0...999] { print(string) } | |
| } | |
| superPrint(string: "test") | |
| let optionalString: String? = "I am optional" | |
| // Error | |
| //superPrint(string: optionalString) | |
| // Optionals | |
| enum Optional2<T> { | |
| case some(T) | |
| case none | |
| } | |
| let optionalInt: Optional<Int> = 3 | |
| let anotherOptionalInt: Int? = Optional.none | |
| let yetAnotherOptionalInt = Optional.some(9) | |
| // if let | |
| if let someInt = optionalInt { | |
| print(someInt) | |
| } | |
| // optional chaining | |
| [1, 2, 3].first?.signum() | |
| // guard | |
| func test() { | |
| guard let anInt = optionalInt else { return } | |
| print(anInt) | |
| } | |
| // ?? nil coalescing | |
| anotherOptionalInt ?? 9 | |
| // force unwrap | |
| yetAnotherOptionalInt! |
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