How To Remove Element From LinkedList?
In this article, we will see, how to remove an element from the LinkedList. The LinkedList class provide various methods to remove an element from the LnikedList. We will cover these methods with examples.
Introduction
The LinkedList class is present in the java.util package.
LinkedList internally uses doubly LinkedList for storing the variables. That’s why LinkedList is preferred when our frequent operation is insertion and deletion.
The LinkedList class has the following methods to remove the object from the LinkedList.
remove()remove(Object o)remove(int index)removeFirst()removeLast()
Let’s see all these methods one by one.
1. remove()
The remove() method retrieves and removes the head (first element) of this list.
The method signature for the remove() method is given below.
1
public E remove()
This method returns the head(first element) of this list. And it does not accept any parameter.
I have given a sample Java program to remove an element from the list using the remove() method.
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import java.util.LinkedList;
/**
* A Java program to remove a head element from
* the linkedList using the remove() method.
*
* @author coderolls.com
*
*/
public class LinkedListRemove {
public static void main(String[] args) {
LinkedList<String> linkedList = new LinkedList<String>();
linkedList.add("BHIM");
linkedList.add("PayTM");
linkedList.add("Freecharge");
linkedList.add("PhonePe");
linkedList.add("JioPay");
System.out.println("LinkedList before removing an element:");
System.out.println(linkedList);
// removes head(first element) i.e. removes BHIM
linkedList.remove();
System.out.println("\nLinkedList after removing an element using remove() method:");
System.out.println(linkedList);
}
}
Output:
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LinkedList before removing an element:
[BHIM, PayTM, Freecharge, PhonePe, JioPay]
LinkedList after removing an element using remove():
[PayTM, Freecharge, PhonePe, JioPay]
Exceptions
The remove() method throws NoSuchElementException if this list is empty.
2. remove(Object o)
The remove(Object o) method removes the first occurrence of the specified element in a list, if it is present.
If the list does not contain the specified element, there will be no change in the list.
The method signature for the remove(Object o) method is given below.
1
public boolean remove(Object o)
This method accepts a parameter Object o, which needs to be removed from the list.
This method returns a boolean value. It will return true if the list got changed as a result of this method call, otherwise false.
I have given a sample Java program to remove an element from the list using the remove(int index) method.
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import java.util.LinkedList;
/**
* A Java program to remove the specified element from
* the linkedList using the remove(Object o) method.
*
* @author coderolls.com
*
*/
public class LinkedListRemoveObject {
public static void main(String[] args) {
LinkedList<String> linkedList = new LinkedList<String>();
linkedList.add("BHIM");
linkedList.add("PayTM");
linkedList.add("Freecharge");
linkedList.add("PhonePe");
linkedList.add("JioPay");
System.out.println("LinkedList before removing an element:");
System.out.println(linkedList);
// removes the specified element i.e. removes Freecharge
linkedList.remove("Freecharge");
System.out.println("\nLinkedList after removing an element using the remove(Object o) method:");
System.out.println(linkedList);
}
}
Output:
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LinkedList before removing an element:
[BHIM, PayTM, Freecharge, PhonePe, JioPay]
LinkedList after removing an element using the remove(Object o) method:
[BHIM, PayTM, PhonePe, JioPay]
Exceptions
The remove() method throws NoSuchElementException if this list is empty.
3. remove(int index)
The remove(int index) method removes the element at the specified position (index) in this list.
Once, this method removes the element, it shifts any subsequent elements to the left (subtracts one from their indices).
The method signature for the remove(Object o) method is given below.
1
public E remove(int index)
This method returns the element that was removed from the list.
I have given a sample Java program to remove an element from the list using the remove(int index) method.
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import java.util.LinkedList;
/**
* A Java program to remove elements at the specified position i.e. index
* from the linkedList using the remove(int index) method.
*
* @author coderolls.com
*/
public class LinkedListRemoveObjectByIndex {
public static void main(String[] args) {
LinkedList<String> linkedList = new LinkedList<String>();
linkedList.add("BHIM");
linkedList.add("PayTM");
linkedList.add("Freecharge");
linkedList.add("PhonePe");
linkedList.add("JioPay");
System.out.println("LinkedList before removing an element:");
System.out.println(linkedList);
// removes the element at index 3 i.e. removes PhonePe
linkedList.remove(3);
System.out.println("\nLinkedList after removing an element using the remove(int index) method:");
System.out.println(linkedList);
}
}
Output:
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LinkedList before removing an element:
[BHIM, PayTM, Freecharge, PhonePe, JioPay]
LinkedList after removing an element using the remove(int index) method:
[BHIM, PayTM, Freecharge, JioPay]
Exceptions
The remove(int index) method throws IndexOutOfBoundsException - if the index is out of range (index < 0 || index >= size())
4. removeFirst()
The removeFirst() method removes and returns the first element from this list.
The method signature for the remove(Object o) method is given below.
1
public E removeFirst()
This method does not accept any parameter and it will return the first element from this list.
I have given a sample Java program to remove the first element from the list using the removeFirst() method.
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import java.util.LinkedList;
/**
* A Java program to remove the first element from
* the linkedList using the removeFirst() method.
*
* @author coderolls.com
*
*/
public class LinkedListRemoveFirst {
public static void main(String[] args) {
LinkedList<String> linkedList = new LinkedList<String>();
linkedList.add("BHIM");
linkedList.add("PayTM");
linkedList.add("Freecharge");
linkedList.add("PhonePe");
linkedList.add("JioPay");
System.out.println("LinkedList before removing an element:");
System.out.println(linkedList);
// removes first element i.e. removes BHIM
linkedList.removeFirst();
System.out.println("\nLinkedList after removing an element using the removeFirst() method:");
System.out.println(linkedList);
}
}
Output:
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LinkedList before removing an element:
[BHIM, PayTM, Freecharge, PhonePe, JioPay]
LinkedList after removing an element using the removeFirst() method:
[PayTM, Freecharge, PhonePe, JioPay]
Exceptions
The remove() method throws NoSuchElementException if this list is empty.
5. removeLast()
The removeLast() method removes and returns the last element from this list.
The method signature for the removeLast() method is given below.
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public E removeLast()
This method does not accept any parameter and it will return the last element from this list.
I have given a sample Java program to remove the last element from the list using the removeLast() method.
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import java.util.LinkedList;
/**
* A Java program to remove the last element from
* the linkedList using the removeLast() method.
*
* @author coderolls.com
*
*/
public class LinkedListRemoveLast {
public static void main(String[] args) {
LinkedList<String> linkedList = new LinkedList<String>();
linkedList.add("BHIM");
linkedList.add("PayTM");
linkedList.add("Freecharge");
linkedList.add("PhonePe");
linkedList.add("JioPay");
System.out.println("LinkedList before removing an element:");
System.out.println(linkedList);
// removes first element i.e. removes BHIM
linkedList.removeLast();
System.out.println("\nLinkedList after removing an element using the removeLast() method:");
System.out.println(linkedList);
}
}
Output:
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LinkedList before removing an element:
[BHIM, PayTM, Freecharge, PhonePe, JioPay]
LinkedList after removing an element using the removeLast() method:
[BHIM, PayTM, Freecharge, PhonePe]
Exceptions
The remove() method throws NoSuchElementException if this list is empty.
Conclusion
In the above tutorial, I have shared 5 methods to remove an element from the LinkedList. These 5 methods are as given below.
-
remove()- Retrieves and removes the head (first element) of this list.1 2
//head (First element) will be removed from the LinkedList linkedList.remove();
-
remove(Object o)- Removes the first occurrence of the specified element in a list.1 2
//'obj' will be removed form the linkedList linkedList.remove(obj);
-
remove(int index)- Removes the element at the specified position in this list.1 2
//The element at index 3 will be removed from the LinkedList linkedList.remove(3);
-
removeFirst()- Removes and returns the first element from this list.1 2
// first element will be removed from the LinkedList linkedList.removeFirst();
-
removeLast()- Removes and returns the last element from this list.1 2
// last element will be removed from the LinkedList linkedList.removeLast();
The example java programs given in the above tutorial can be found at this GitHub Repository.
Let me know you thoughts or suggestions on the topic discussed above in comment section below.
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