Arraylist.contains() in Java
Last Updated :
07 May, 2023
In Java, ArrayList contains() method in Java is used for checking if the specified element exists in the given list or not.
Syntax of Java ArrayList contains() :
public boolean contains(Object)
object-element to be searched for
Parameters: object- element whose presence in this list is to be tested
Returns: It returns true if the specified element is found in the list else it returns false.
Java ArrayList contains() examples
Example 1: Demonstrate the working of the method contains() in an integer.
Java
import java.util.ArrayList;
class GFG {
public static void main(String[] args)
{
ArrayList<Integer> arr = new ArrayList<Integer>( 4 );
arr.add( 1 );
arr.add( 2 );
arr.add( 3 );
arr.add( 4 );
boolean ans = arr.contains( 2 );
if (ans)
System.out.println( "The list contains 2" );
else
System.out.println( "The list does not contains 2" );
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
Example 2: Demonstrate the working of the method contains() in the string
Java
import java.util.ArrayList;
class GFG {
public static void main(String[] args)
{
ArrayList<String> arr = new ArrayList<String>( 4 );
arr.add( "geeks" );
arr.add( "for" );
arr.add( "geeks" );
boolean ans = arr.contains( "geeks" );
if (ans)
System.out.println( "The list contains geeks" );
else
System.out.println(
"The list does not contains geeks" );
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
Practical Application
In search operations, we can check if a given element exists in a list or not.
Note: Time Complexity is O(n)
Reference: Oracle Docs
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