Any way to stop a block literal in swift

Question

Like below, i want to stop the literal by something like break

var numbers = [1,2,3,4] numbers.forEach {     if $0 % 2 == 0 {         break     } } 

Answer 1

forEach is not a loop (it is a block passed to a loop, but not a loop itself), or more accurately, forEach is not part of Swift's Control Flow. Which is why you can't use break or continue.

Just use a for-in loop.

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Example :

var numbers = [ 1,2,3,4]  func firstEvenNumber(inArray array: [Int]) -> Int? {      var firstMatch : Int?      for number in numbers {         if (number % 2) == 0 {             firstMatch = number             break         }     }     return firstMatch }  firstEvenNumber(inArray: numbers) // 2 

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You can use return inside the forEach closure, but it does not break the loop, it only returns the block in the current pass.

var numbers = [ 1,2,3,4]  func evenNumbers(inArray: [Int]) -> [Int] {      var matches : [Int] = []      numbers.forEach{         if $0 % 2 == 0 {             matches.append($0)              // early return on even numbers             // does not stop forEach             // comparable to a continue in a for in loop             return         }          // only reached on uneven numbers     }     return matches }  evenNumbers(numbers) // [2,4] 

Answer 2

Since you want to stop on the first match, you should use first and not forEach:

numbers.first { (number) -> Bool in     return number % 2 == 0 } 

Do something with the result (the first even number on the list):

if let firstEvenNumber = numbers.first(where: { $0 % 2 == 0 }) {     print("The first even number on the list is \(firstEvenNumber)") } 

Bonus: create a list of all the even numbers using filter:

let allEvenNumbers = numbers.filter { $0 % 2 == 0 }