CODEWITHSUNDEEP
java
user4593157
user4593157

Reputation: 95

Is there a way that I can compare an array and an arraylist?

Is there a way that I can compare an array and an arraylist like

if (array[0]==arraylist[0])

I am working on this problem:

String[] s= {"a","a","b","b","b","c"};
ArrayList<String> list = new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");
// create a new arraylist that stores the frequency of each character. 
// For example, "a" appears twice in s, so newArrayList[0]=2; "b" appears 
// three times, so newArrayList[1]=3, and so on.

My idea is using a loop to scan through the string array and every time when a letter in it equals the letter in list, int count++. But I dont know how to compare things in an array and things in an arraylist.

Upvotes: 1

Views: 11761

Answers (4)

Ramesh Peetha
Ramesh Peetha

Reputation: 1

import java.util.ArrayList;

public class ArrayAndArrayListElementsComparison {
    public static int compareArrayAndArrayListElements(String[] array, ArrayList<String> arraylist) {
        int count = 0;
        for (String s : array) {
            if (arraylist.contains(s)) {
                count++;
            }
        }
        return count;
    }

    public static void main(String[] args) {
        String[] array = {"a", "a", "b", "b", "b", "c"};
        ArrayList<String> arraylist = new ArrayList<String>();
        System.out.println("");
        arraylist.add("a");
        arraylist.add("b");
        arraylist.add("c");

        if (!arraylist.isEmpty() && array.length > 0) {
            if (compareArrayAndArrayListElements(array, arraylist) == array.length) {
                System.out.println("ArrayList contains all the elements in Array");
            } else if (compareArrayAndArrayListElements(array, arraylist) > 0) {
                System.out.println("ArrayList contains only few elements in Array");
            } else {
                System.out.println("ArrayList contains none of the elements in Array");
            }
        } else {
            System.out.println("Either ArrayList or Array is Empty.");
        }
    }
}

Upvotes: 0

Evgeniy Dorofeev
Evgeniy Dorofeev

Reputation: 136012

Shortest way is this

Arrays.asList(arr).equals(list)

Upvotes: 5

Nam Tran
Nam Tran

Reputation: 62

You try

if (array[0].equals(arraylist[0]))

As in java comparisons string should use equals(). It's not like javascript.

Upvotes: -1

mattm
mattm

Reputation: 5949

Yes, you can iterate through the array and arraylist and compare elements. ArrayList elements are accessed with .get(index). And if you are comparing Objects (non-primitives), you need to use the .equals() method, not ==. 

if(array[i].equals(arrayList.get(i) ) )

Upvotes: 1

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