Replace all A's present in an Array with 15 in Swift 3.0. : Replace  all A's present in an Array with 15 in Swift 3.0. 

Example my array is ["4", "5", "6", "A", "A", "Q", "A"]
 and i want to replace A by 15. Such as my final array becomes  ["4", "5", "6", "15", "15", "Q", "15"].