Swift Quick Reference

let name = "Ada"

var count = 0

let price: Double = 9.99

print("Hello")

print("\(name) is \(age)")

Int("42")  // Int?

String(42)

Double(n)

var nickname: String? = nil

if let nickname {
    print(nickname)
}

guard let user else { return }

let name = nickname ?? "guest"

user?.address?.city

var nums = [3, 1, 2]

nums.append(4)

nums.count

nums.map { $0 * 2 }

nums.filter { $0 > 1 }

nums.reduce(0, +)

nums.sorted()

users.sorted { $0.age < $1.age }

nums.reverse()

nums.reversed()

var ages = ["Ada": 36]
ages["Bob"] = 40
ages["Ada", default: 0]

for n in nums { }

for (key, value) in ages { }

for (i, n) in nums.enumerated() { }

let tags: Set = ["a", "b"]

if x > 0 { } else { }

switch n {
case 0: print("zero")
case 1...9: print("small")
default: print("big")
}

for i in 0..<5 { }

for i in 1...5 { }

func greet(_ name: String, loudly: Bool = false) -> String {
    loudly ? name.uppercased() : name
}

let square = { (n: Int) in n * n }

func load() async throws -> Data {
    let (data, _) = try await URLSession.shared.data(from: url)
    return data
}

struct Point {
    var x: Int
    var y: Int
}

class Dog {
    let name: String
    init(name: String) { self.name = name }
}

enum Shape {
    case circle(radius: Double)
    case square(size: Double)
}

protocol Shape {
    func area() -> Double
}

extension Int {
    var isEven: Bool { self % 2 == 0 }
}

do {
    try risky()
} catch {
    print(error)
}