Arraylist.contains() in Java
Last Updated :
07 May, 2023
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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
// Java code to demonstrate the working of// contains() method in ArrayList// for ArrayList functionsimport java.util.ArrayList;class GFG { public static void main(String[] args) { // creating an Empty Integer ArrayList ArrayList<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
Example 2: Demonstrate the working of the method contains() in the string
Java
// Java code to demonstrate the working of// contains() method in ArrayList of string// for ArrayList functionsimport java.util.ArrayList;class GFG { public static void main(String[] args) { // creating an Empty String ArrayList ArrayList<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
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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