Java ArrayList remove() Method

Java ArrayList

The remove() method is used to delete a single element from the dynamic array.

The syntax for the remove() method is:

// Remove specified element
arraylist.remove(Object obj)

// Remove element at specified index
arraylist.remove(int index)

Note: arraylist is an object of the ArrayList class.

Parameter Description:

obj - The element to be removed
index - The index of the element to be removed

If the obj element appears multiple times, the first occurrence in the dynamic array is removed.

Return Value

If an element is passed, it returns true if the element is successfully removed.

If an index is passed, it returns the removed element.

Note: If the specified index is out of range, this method throws an IndexOutOfBoundsException.

Example

Removing a specified element from the array:

Example

import java.util.ArrayList;

class Main {
    public static void main(String[] args) {
        // Create an array
        ArrayList<String> sites = new ArrayList<>();

        sites.add("Google");
        sites.add("tutorialpro");
        sites.add("Taobao");
        System.out.println("Website List: " + sites);

        // Remove element Taobao
        boolean result = sites.remove("Taobao");
        System.out.println("Is Taobao deleted? " + result);
        System.out.println("After using remove(): " + sites);
    }
}

Output:

Website List: [Google, tutorialpro, Taobao]
Is Taobao deleted? true
After using remove(): [Google, tutorialpro]

In the above example, we used the remove() method to delete "Taobao" from the dynamic array.

Removing an element from a specified position:

Example

import java.util.ArrayList;

class Main {
    public static void main(String[] args) {
        // Create an array
        ArrayList<String> sites = new ArrayList<>();

        sites.add("Google");
        sites.add("tutorialpro");
        sites.add("Taobao");
        System.out.println("Website List: " + sites);

        // Remove element at index 2
        String element = sites.remove(2);
        System.out.println("After using remove(): " + sites);
        System.out.println("Removed element: " + element);
    }
}

Output:

Website List: [Google, tutorialpro, Taobao]
After using remove(): [Google, tutorialpro]
Removed element: Taobao

Removing the first occurrence of an element:

Example

import java.util.ArrayList;

class Main {
    public static void main(String[] args) {
        // Create an array
        ArrayList<Integer> randomNumbers = new ArrayList<>();

        // Insert elements into the array
        randomNumbers.add(22);
        randomNumbers.add(13);
        randomNumbers.add(35);
        randomNumbers.add(13);
        randomNumbers.add(40);

        // Remove the first occurrence of 13
        boolean result = randomNumbers.remove(Integer.valueOf(13));
        System.out.println("Is 13 deleted? " + result);
        System.out.println("After using remove(): " + randomNumbers);
    }
}

Output:

Is 13 deleted? true
After using remove(): [22, 35, 13, 40]

System.out.println("ArrayList: " + randomNumbers);

// Remove the first occurrence of the element 13
boolean result = randomNumbers.remove(Integer.valueOf(13));
System.out.println("Was 13 removed? " + result);
System.out.println("After using remove(): " + randomNumbers);
}
}

The output of the above program is:

ArrayList: [22, 13, 35, 13, 40]
Was 13 removed? true
After using remove(): [22, 35, 13, 40]

In the example above, we created a dynamic array named randomNumbers. In this array, the element 13 appears twice. Note this line:

randomNumbers.remove(Integer.valueOf(13))

Integer.valueOf() converts 13 from an int type to an Integer object. Since the remove() method only takes an object as its parameter.

remove() is used to remove the first occurrence of 13 in the array.

Note: We can also use the clear() method to remove all elements from the array. For more information, visit Java ArrayList clear().

Java ArrayList

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