\n
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;<\/p>\n
public class Main {<\/p>\n
public static void main(String[] args) {
Set<String> hash_Set = new HashSet<>();<\/p>\n
hash_Set.add(“program”);
hash_Set.add(“to”);
hash_Set.add(“demonstrate”);
hash_Set.add(“set”);
hash_Set.add(null);
System.out.println(hash_Set);<\/p>\n
\/\/ Remove an element
hash_Set.remove(null);
System.out.println(hash_Set);
\/\/ Verify presence of an element
System.out.println(hash_Set.contains(“program”));<\/p>\n
\/\/Iterate thru for each loop<\/p>\n
for (String s : hash_Set) {
System.out.print(s + ” “);
}
System.out.println();
\/\/Iterate thru Iterator;<\/p>\n
Iterator<String> itr = hash_Set.iterator();
while (itr.hasNext()) {
System.out.print(itr.next() + ” “);
}
}<\/p>\n
}<\/p>\n
Output \u2013 <\/p>\n[null, set, program, to, demonstrate]
[set, program, to, demonstrate]
true
set program to demonstrate
set program to demonstrate<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n
\n
How can we have an Ordered Set?<\/h3>\n
We can use LinkedHashSet class to achieve this. LinkedHashSet extends Hashset class, so it inherits all properties of HashSet, but additionally offers ordering of element based on insertion sequence. <\/p>\n
Example<\/strong><\/p>\n<\/div>\n\n
<\/div>\n
\n
\n
import java.util.LinkedHashSet;
import java.util.Set;<\/p>\n
public class Main {<\/p>\n
public static void main(String[] args) {
Set<String> linkedhashset = new LinkedHashSet<>();<\/p>\n
linkedhashset.add(“program”);
linkedhashset.add(“to”);
linkedhashset.add(“demonstrate”);
linkedhashset.add(“linked hash set”);<\/p>\n
System.out.println(linkedhashset);<\/p>\n
}
}<\/p>\n
Output<\/p>\n[program, to, demonstrate, linked hash set]<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n
\n
Explanation<\/strong><\/p>\nThe insertion order is maintained while printing the values of the LinkedHashSet.<\/p>\n
How can we sort a Set?<\/h3>\n
There is no direct support to sort elements in a Set. But we can use TreeSet class to achieve this. Let\u2019s see this in an example. <\/p>\n
Example<\/strong><\/p>\n<\/div>\n\n
<\/div>\n
\n
\n
import java.util.Set;
import java.util.TreeSet;<\/p>\n
public class Main {<\/p>\n
public static void main(String[] args) {
Set<String> treeset = new TreeSet<>();<\/p>\n
treeset.add(“program”);
treeset.add(“to”);
treeset.add(“demonstrate”);
treeset.add(“tree set”);<\/p>\n
System.out.println(treeset);<\/p>\n
}
}<\/p>\n
Output<\/p>\n[demonstrate, program, to, tree set]<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n
\n
Explanation
<\/strong>
Even if the inserted words in the TreeSet are not in sorted manner, when we print the elements, they are printed in sorted manner.<\/p>\nHow to convert a Set to a List and vice versa?<\/h3>\n
List to Set Example<\/p>\n<\/div>\n
\n
<\/div>\n
\n
\n
public class Main {<\/p>\n
public static void main(String[] args) {
List<String> list = new ArrayList<>();
list.add(“Asia”);
list.add(“Asia”);
list.add(“Europe”);
list.add(“North America”);<\/p>\n
Set<String> set = new TreeSet<>();
set.addAll(list);
for (String s : set)
{
System.out.println(s);
}<\/p>\n
}
}<\/p>\n
Output<\/p>\nAsia
Europe
North America<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n
\n
Explanation
<\/strong>
First, we create a List and add few elements in it. Then we create a TreeSet and using addAll() method, we insert all elements of the List to the TreeSet and print the values in the console.
The important thing to observe here is, even though the List have a duplicate item, TreeSet did not allow that. So, we can remove the duplicates of List using this mechanism.<\/p>\nSet to List Example<\/strong><\/p>\n<\/div>\n\n
<\/div>\n
\n
\n
import java.util.*;<\/p>\n
public class Main {<\/p>\n
public static void main(String[] args) {
Set<String> set = new HashSet<>();
set.add(“123”);
set.add(“456”);
set.add(“555”);
set.add(“421”);<\/p>\n
List<String> list = new ArrayList<>();
list.addAll(set);
for (String s : list)
{
System.out.println(s);
}<\/p>\n
}
}<\/p>\n
Output<\/p>\n123
421
456
555<\/span><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n
<\/div>\n<\/section>\n
<\/body><\/html><\/p>\n","protected":false},"excerpt":{"rendered":"
table of contents What is Set interface? Describe different operations possible on a Set? How can we have an Ordered Set? How can we sort a Set? How to convert a Set to a List and vice versa? What is Set interface? The set interface present in java.util package extends Collection interface. It is an […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-638","post","type-post","status-publish","format-standard","hentry","category-java","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/posts\/638","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=638"}],"version-history":[{"count":0,"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/posts\/638\/revisions"}],"wp:attachment":[{"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=638"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=638"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rahulshettyacademy.com\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=638"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}