dictAddingVal.swift

var dict = ["blue": 2, "grey": 1, "red": 2]
var newDict = ["pink": 3, "red": 5]

dict.merge(newDict) { (current, _) in current } // ["blue": 2, "grey": 1, "red": 2, "pink": 3]
dict.merge(newDict) { (_, new) in new }         // ["blue": 2, "grey": 1, "red": 5, "pink": 3]

let mergedDict = dict.merging(newDict) { (current, _) in current}  // ["blue": 2, "grey": 1, "red": 5, "pink": 3]