every function tests all elements in a Swift 3 sequence. Example usage: var allOdd = [1, 5, 37].every { $0 % 2 == 1 }

Sequence

public extension Sequence {
    
    //  return true if all elements return true
    func every<T>(predicate:(T) -> Bool) -> Bool {
        for item in self {
            if !predicate(item as! T) {
                return false
            }
        }
        return true
    }
}