In this article, we will discuss an example on how to search, whether particular element present in HashSet or NOT
Searching element from HashSet :
Method signature:
boolean contains(Object o);
- This method is used to search specified object from invoking collection
- Returns true, if present; otherwise return false
SearchElementFromHashSet.java
package in.bench.resources.java.collections; import java.util.HashSet; public class SearchElementFromHashSet { public static void main(String[] args) { // creating HashSet object of type String HashSet<String> ceo = new HashSet<String>(); // adding elements to HashSet object ceo.add("Sundar Pichai"); ceo.add("Satya Nadella"); ceo.add("Shiv Nadar"); ceo.add("Shantanu Narayen"); ceo.add("Sundar Pichai"); // duplicate object ceo.add("Francisco D’Souza"); ceo.add(null); // null is allowed // Iterating using for-loop System.out.println("Iterating HashSet\n"); for(String founder : ceo) { System.out.println(founder); } // searching element boolean boolElement = ceo.contains("Sundar Pichai"); System.out.println("\n\nWhether element 'Sundar Pichai' " + "is present : " + boolElement); // searching and printing in same line System.out.println("\n\nWhether element 'Shiv Nadar' " + "is present : " + ceo.contains("Shiv Nadar")); // searching and printing in same line System.out.println("\n\nWhether element 'Nandan Nilekeni' " + "is present : " + ceo.contains("Nandan Nilekeni")); } }
Output:
Iterating HashSet null Satya Nadella Shiv Nadar Francisco D’Souza Shantanu Narayen Sundar Pichai Whether element 'Sundar Pichai' is present : true Whether element 'Shiv Nadar' is present : true Whether element 'Nandan Nilekeni' is present : false
From above example, HashSet
- allows only unique elements
- null object is allowed (max of 1)
- retrieve items in random-order, while iterating
References:
- https://docs.oracle.com/javase/tutorial/collections/intro/
- https://docs.oracle.com/javase/tutorial/collections/interfaces/collection.html
- https://docs.oracle.com/javase/7/docs/api/java/util/Collection.html
- https://docs.oracle.com/javase/7/docs/api/java/util/Enumeration.html
- https://docs.oracle.com/javase/7/docs/api/java/util/Iterator.html
- https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html
- https://docs.oracle.com/javase/7/docs/api/java/util/ListIterator.html
Happy Coding !!
Happy Learning !!