ZipWithKeySwift

ZipWithKey.swift

//: Playground - noun: a place where people can play

import UIKit

struct Person {
    let name: String
    let age: Int
}

struct Car {
    let owner: String
    let license: String
}

let persons = [Person(name: "Benji", age: 20), Person(name: "Jaron", age: 32)]
let cars = [Car(owner: "Jaron", license: "JXYZ"), Car(owner: "Benji", license: "XYZ")]

func zipWithKey<Type1, Type2, KeyType: Hashable>(
    array1: [Type1],
    array2: [Type2],
    keyFunction1: (Type1) -> KeyType,
    keyFunction2: (Type2) -> KeyType
) -> [(Type1, Type2)] {
    var hashTable: [KeyType: Type1] = [:]

    for element in array1 {
        hashTable[keyFunction1(element)] = element
    }

    var result: [(Type1, Type2)] = []

    for element in array2 {
        guard let type1Counterpart = hashTable[keyFunction2(element)] else {
            continue
        }

        result.append((type1Counterpart, element))
    }

    return result
}

let x = zipWithKey(persons, array2: cars, keyFunction1: { $0.name }, keyFunction2: { $0.owner })

print(x)