클로저의 형식 추론

let numbers = [1, 2, 3, 4]
let doubled = numbers.map { $0 * 2 }
print(doubled)

let names = ["ada", "bob"]
let upper = names.map { $0.uppercased() }
print(upper)

let nums = [1, 2, 3, 4, 5]
let evens = nums.filter { $0 % 2 == 0 }
print(evens)

let sums = zip([1, 2, 3], [10, 20, 30]).map { $0 + $1 }
print(Array(sums))

let nums = [3, 1, 2]
let sorted = nums.sorted { (a: Int, b: Int) -> Bool in
    return a < b
}
print(sorted)

let add: (Int, Int) -> Int = { a, b in a + b }
print(add(2, 3))

let result = [5, 3, 8, 1].sorted { $0 > $1 }
print(result)

let total = [1, 2, 3, 4].reduce(0) { acc, x in acc + x }
print(total)

let lengths = ["hi", "hello", "hey"].map { $0.count }
print(lengths)

let transform: (String) -> Int = { $0.count }
print(transform("swift"))

let isPositive: (Int) -> Bool = { n in n > 0 }
print(isPositive(5), isPositive(-3))

let f: (Int) -> Int = { $0 + 1 }
let xs = [1, 2, 3].map { $0 * 10 }
print(f(9), xs)