Swift - How to get indexes of filtered items of array

Question

let items: [String] = [\"A\", \"B\", \"A\", \"C\", \"A\", \"D\"]

items.whatFunction(\"A\") // -> [0, 2, 4]
items.whatFunction(\"B\") // -> [1]

Answer 1

You can use that below code:

var firstArray = ["k","d","r","r","p","k","b","p","k","k"]
var secondArray = ["k","d","r","s","d","r","b","c"]

let filterArray = firstArray.filter { secondArray.contains($0) }
let filterArray1 = firstArray.filter { !secondArray.contains($0) }
let filterIndex = firstArray.enumerated().filter { $0.element == "k" }.map { $0.offset }
print(filterArray) --> // ["k", "d", "r", "r", "k", "b", "k", "k"]
print(filterArray1) --> // ["p", "p"]
print(filterIndex) --> // [0, 5, 8, 9]