Search Elements of LinkedList in Java with Example

Java LinkedList class provides the following methods to search an element of LinkedList in Java:
  • contains(Object o)
  • indexOf(Object o)
  • lastIndexOf(Object o)

Search Elements of LinkedList in Java with Example

Let's create a list of employees and apply LinkedList search methods.
LinkedList<String> employees = new LinkedList<>();

employees.add("John");
employees.add("David");
employees.add("Lara");
employees.add("Chris");
employees.add("Steve");
employees.add("David");

contains(Object o)

Check if the LinkedList contains an element
System.out.println("Does Employees LinkedList contain \"Lara\"? : " + employees.contains("Lara"));

indexOf(Object o)

Find the index of the first occurrence of an element in the LinkedList
System.out.println("indexOf \"Steve\" : " + employees.indexOf("Steve"));
System.out.println("indexOf \"Mark\" : " + employees.indexOf("Mark"));

lastIndexOf(Object o)

Find the index of the last occurrence of an element in the LinkedList
System.out.println("lastIndexOf \"David\" : " + employees.lastIndexOf("David"));
System.out.println("lastIndexOf \"Bob\" : " + employees.lastIndexOf("Bob"));

Complete Example

package com.javaguides.collections.linkedlistexamples;

import java.util.LinkedList;

public class SearchLinkedListExample {
    public static void main(String[] args) {
        LinkedList < String > employees = new LinkedList < > ();

        employees.add("John");
        employees.add("David");
        employees.add("Lara");
        employees.add("Chris");
        employees.add("Steve");
        employees.add("David");

        // Check if the LinkedList contains an element
        System.out.println("Does Employees LinkedList contain \"Lara\"? : " + employees.contains("Lara"));

        // Find the index of the first occurrence of an element in the LinkedList
        System.out.println("indexOf \"Steve\" : " + employees.indexOf("Steve"));
        System.out.println("indexOf \"Mark\" : " + employees.indexOf("Mark"));

        // Find the index of the last occurrence of an element in the LinkedList
        System.out.println("lastIndexOf \"David\" : " + employees.lastIndexOf("David"));
        System.out.println("lastIndexOf \"Bob\" : " + employees.lastIndexOf("Bob"));
    }
}

Output

Does Employees LinkedList contain "Lara"? : true
indexOf "Steve" : 4
indexOf "Mark" : -1
lastIndexOf "David" : 5
lastIndexOf "Bob" : -1

Reference



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