Removing Elements from an Array or ArrayList in Java

In an array, a size is always fixed. Therefore, it is impossible to delete an element directly. However, collections such as ArrayLists can be used that have the functionality to be dynamically resized. This can be accomplished easily by removing elements of an array and converting it into an ArrayList for more dynamic array management in Java. The following are the ways to remove an element of an array

• Removing elements by index and value from a string ArrayList

• Removing elements by index and checking the size in an integer ArrayList

Removing Elements by Index & Value from a String ArrayList

The remove(int index) method is used to remove an element at a specific index and the remove(Object o) method to remove an element by its value.

Syntax

The following is the syntax for java.util.ArrayList.remove() method

public E remove(int index)

Example

The following is an example of removing elements by index and value from a string ArrayList

import java.util.ArrayList;

public class Main {
   public static void main(String[] args) {
      ArrayList objArray = new ArrayList();
      objArray.clear();
      objArray.add(0,"0th element");
      objArray.add(1,"1st element");
      objArray.add(2,"2nd element");
      System.out.println("Array before removing an element"+objArray);
      objArray.remove(1);
      objArray.remove("0th element");
      System.out.println("Array after removing an element"+objArray);
   }
}

Output

Array before removing an  element[0th element, 1st element, 2nd element]
Array after removing an element[2nd element]

Removing Elements by Index & Checking size in an Integer ArrayList

The elements are removed from an ArrayList of integers using the remove(int index) method. Then the size() method is used to display the number of elements in the ArrayList before and after removal.

Example 2

The following is an example of removing elements by index and checking the size in an integer ArrayList

import java.util.ArrayList;

public class ArrayListDemo {
   public static void main(String[] args) {
      // Use generic ArrayList to store Integer values
      ArrayList arr = new ArrayList(5);
      arr.add(20);
      arr.add(15);
      arr.add(30);
      arr.add(45);
      
      System.out.println("Size of list: " + arr.size());
      
      // Iterate over the ArrayList using enhanced for loop
      for (Integer number : arr) {
         System.out.println("Number = " + number);
      } 
      
      // Remove element at index 2
      arr.remove(2);
      System.out.println("Now, Size of list: " + arr.size());
      
      // Iterate again after removal
      for (Integer number : arr) {
         System.out.println("Number = " + number);
      } 
   }
} 

Output

Size of list: 4
Number = 20
Number = 15
Number = 30
Number = 45
Now, Size of list: 3
Number = 20
Number = 15
Number = 45    .