Comparing two ArrayList In Java
Java provides a method for comparing two Array List. The ArrayList.equals() is the method used for comparing two Array List. It compares the Array lists as, both Array lists should have the same size, and all corresponding pairs of elements in the two Array lists are equal.
Example:
Input : ArrayList1 = [1, 2, 3, 4],
ArrayList2 = [1, 2, 3, 4]
Output: Array List are equal
Input : ArrayList1 = [1, 2, 3, 4],
ArrayList2 = [4, 2, 3, 1]
Output: Array List are not equal
Syntax:
boolean equals(Object o)
Parameters: This function has a single parameter which is an object to be compared for equality.
Returns: This method returns True if Array lists are equal.
Implementation:
Java
import java.util.ArrayList;
public class GFG {
public static void main(String[] args)
{
ArrayList<String> ArrayList1
= new ArrayList<String>();
ArrayList<String> ArrayList2
= new ArrayList<String>();
ArrayList1.add( "item 1" );
ArrayList1.add( "item 2" );
ArrayList1.add( "item 3" );
ArrayList1.add( "item 4" );
ArrayList2.add( "item 1" );
ArrayList2.add( "item 2" );
ArrayList2.add( "item 3" );
ArrayList2.add( "item 4" );
System.out.println( " ArrayList1 = " + ArrayList2);
System.out.println( " ArrayList1 = " + ArrayList1);
if (ArrayList1.equals(ArrayList2) == true ) {
System.out.println( " Array List are equal" );
}
else
{
System.out.println( " Array List are not equal" );
}
System.out.println(
"\n Lets insert one more item in Array List 1" );
ArrayList1.add( "item 5" );
System.out.println( " ArrayList1 = " + ArrayList1);
System.out.println( " ArrayList = " + ArrayList2);
if (ArrayList1.equals(ArrayList2) == true ) {
System.out.println( " Array List are equal" );
}
else {
System.out.println( " Array List are not equal" );
}
}
}
|
Output
ArrayList1 = [item 1, item 2, item 3, item 4]
ArrayList1 = [item 1, item 2, item 3, item 4]
Array List are equal
Lets insert one more item in Array List 1
ArrayList1 = [item 1, item 2, item 3, item 4, item 5]
ArrayList = [item 1, item 2, item 3, item 4]
Array List are not equal
Time Complexity: O(N), where N is the length of the Array list.
Last Updated :
07 Oct, 2022
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