Compare the values in two different arrays

Question

I am trying to compare the values of two arrays in Swift. If a value of array2 is not found in array1 all the array2 found values need to be list and deleted.

I was trying to use the code below but its not working anymore in Swift 2:

let array1 = [["aaa","12"],["bbb","349"],["ccc","91"],["ddd","143"]]
let array2 = ["aaa","SSS","bbb","ccc","QQQ","ZZZ","ddd"]

let notNeededValues = filter(enumerate(zip(array1,array2))) { $1.0 == $1.1 }.map{ $0.0 }

print(notNeededValues)

Answer 1

Not sure if I understand your problem correctly, but the problem seems to be, that your code needs a simple conversion to Swift 2 syntax:

let array1 = [["aaa","12"],["bbb","349"],["ccc","91"],["ddd","143"]]
let array2 = ["aaa","SSS","bbb","ccc","QQQ","ZZZ","ddd"]

let notNeededValues = zip(array1, array2).enumerate().filter { $1.0 == $1.1 }.map { $0.0 }

print(notNeededValues)

Swift is moving away from globally defined functions, like filter and enumerate once were, and is using dot-syntax instead. This change was made possible by protocol extensions, and makes code more readable.

---

Update:

I assume this is what you mean(?):

let notNeededValues = array2.filter { !array1.map { $0[0] }.contains($0) }

// or like this:
let array1FirstElements = array1.map { $0[0] }
let notNeededValues = array2.filter { !array1FirstElements.contains($0) }

Answer 2

How about this:

let array1 = [["aaa","12"],["bbb","349"],["ccc","91"],["ddd","143"]]
let array2 = ["aaa","SSS","bbb","ccc","QQQ","ZZZ","ddd"]

extension Array where Element: Equatable {
    func removeObject(object: Element) -> [Element] {
        return filter {$0 != object}
    }
}

var filteredArray2 = array2.reduce(array2) {
    if array1.flatMap({$0}).contains($1) {
        return $0.removeObject($1)
    }
    return $0
}

print(filteredArray2)