List contains() method in Java with Examples
Last Updated :
03 Dec, 2024
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The contains() method of List interface in Java is used for checking if the specified element exists in the given list or not.
Example:
// Java Program to Demonstrate
// List contains() Method
import java.util.*;
class GFG
{
public static void main (String[] args)
{
List<Integer> l = new ArrayList<>();
l.add(1);
l.add(2);
// Cheking List contains 2
System.out.println("List contains 2 : " + l.contains(2));
// Cheking List contains 3
System.out.println("List contains 3 : " + l.contains(3));
}
}
Output
List contains 2 : true List contains 3 : false
Syntax of Method
public boolean contains(Object obj)
- Parameters: This method accepts a single parameter obj whose presence in this list is to be tested.
- Return Value: It returns true if the specified element is found in the list else it returns false.
Practical Application : In search operations, we can check if a given element exists in a list or not.
Example of List contains() Method
Below programs illustrate the contains() method in List:
Program 1: Demonstrate the working of the method contains() in List of integer.
// Java code to demonstrate the working of
// contains() method in List interface
import java.util.*;
class GFG {
public static void main(String[] args)
{
// creating an Empty Integer List
List<Integer> arr = new ArrayList<Integer>(4);
// using add() to initialize values
// [1, 2, 3, 4]
arr.add(1);
arr.add(2);
arr.add(3);
arr.add(4);
// use contains() to check if the element
// 2 exits or not
boolean ans = arr.contains(2);
if (ans)
System.out.println("The list contains 2");
else
System.out.println("The list does not contains 2");
// use contains() to check if the element
// 5 exits or not
ans = arr.contains(5);
if (ans)
System.out.println("The list contains 5");
else
System.out.println("The list does not contains 5");
}
}
Output
The list contains 2 The list does not contains 5
Program 2: Demonstrate the working of the method contains() in List of string.
// Java code to demonstrate the working of
// contains() method in List of string
import java.util.*;
class GFG {
public static void main(String[] args)
{
// creating an Empty String List
List<String> arr = new ArrayList<String>(4);
// using add() to initialize values
// ["geeks", "for", "geeks"]
arr.add("geeks");
arr.add("for");
arr.add("geeks");
// use contains() to check if the element
// "geeks" exits or not
boolean ans = arr.contains("geeks");
if (ans)
System.out.println("The list contains geeks");
else
System.out.println("The list does not contains geeks");
// use contains() to check if the element
// "coding" exits or not
ans = arr.contains("coding");
if (ans)
System.out.println("The list contains coding");
else
System.out.println("The list does not contains coding");
}
}
Output
The list contains geeks The list does not contains coding
Reference: Click here to check the official document
