At one of the iOS developer interviews I went, I was asked to replicate the functionality of a Dictionary. I thought I would share what I came up with. Improvements are most welcome.

Dictionary.playground

import Foundation

// This class simulates SWift's dictionary class
class MyDictionary <Key: Equatable, Value> {
    private var values: [Value] = []
    private var keys: [Key] = []
    
    func set(value: Value, key: Key) {
        if keys.contains(key), let index = keys.firstIndex(of: key) {
            values[index] = value
        } else {
            values.append(value)
            keys.append(key)
        }
    }
    
    func get(key: Key) -> Value? {
        if let index = keys.firstIndex(of: key) {
            return values[index]
        }
        return nil
    }
}

var dic: MyDictionary<String, String> = MyDictionary()
dic.set(value: "Sam", key: "ceo")
dic.set(value: "Sam Inc.", key: "company")
dic.set(value: "20", key: "employees")

print("Company: " + (dic.get(key: "company") ?? ""))
print("CEO: " + (dic.get(key: "ceo") ?? ""))
print("Number of employees: " + (dic.get(key: "employees") ?? ""))

dic.set(value: "30", key: "employees")
print("Number of employees: " + (dic.get(key: "employees") ?? ""))