Week 3: Objects, files and exceptions/11b. Combine names and grades

Write the method

public static HashMap<String, Integer> combine(ArrayList<String> names, ArrayList<Integer> grades)

which takes a list of names and grades as parameters. 
Create and return a new hashmap of names and grades, with names as keys and grades as values. 
The names and grades are listed at the corresponding indexes (i.e., the first name and the first grade belong together).




Example execution:

public static void main(String[] args){
    ArrayList<String> names = new ArrayList<>();
    ArrayList<Integer> grades = new ArrayList<>();

    names.add("Axel");
    names.add("Ann");
    names.add("Michael");

    grades.add(9);
    grades.add(8);
    grades.add(10);

    HashMap<String, Integer> hm = combine(names, grades);
    System.out.println(hm);
}

Program outputs:
{Axel=9, Michael=10, Ann=8}



==========================================================






import java.util.Random;
import java.util.ArrayList;
import java.util.HashMap;

public class Test{
    public static void main(String[] args){
        final Random r = new Random();
        
        
        String[] nn = "Jack Joseph Lisa Lena Maya Kim".split(" ");
        
        ArrayList<String> nimet = new ArrayList<>();
        ArrayList<Integer> arvosanat = new ArrayList<>();
        
        for (String nimi : nn) {
            nimet.add(nimi);
            arvosanat.add(r.nextInt(7) + 4);
        }
        
        System.out.println("Names: " + nimet);
        System.out.println("Grades: " + arvosanat);
        System.out.println("Combined: ");
        
        HashMap<String, Integer> taulu = combine(nimet, arvosanat);
        
        for (String nimi : nimet) {
            System.out.println(nimi + ": " + taulu.get(nimi));
        }
        
    }






    public static HashMap<String, Integer> combine(ArrayList<String> names, ArrayList<Integer> grades) {
        HashMap<String, Integer> map = new HashMap<>();
        for (int i = 0; i < names.size(); i++) {
            map.put(names.get(i), grades.get(i));
        }
        return map;
    }





}






Names: [Jack, Joseph, Lisa, Lena, Maya, Kim]
Grades: [4, 4, 8, 8, 8, 7]
Combined: 
Jack: 4
Joseph: 4
Lisa: 8
Lena: 8
Maya: 8
Kim: 7