Demo — https://youtu.be/2tLxcaopKR4
public class SetDemo {
public static void main(String[] args) {
//Initializing a new HashSet
HashSet<String> mySet = new HashSet<>();
//Adding values to set
mySet.add("One");
mySet.add("Two");
mySet.add("Two");
mySet.add("Three");
//Printing set
System.out.println(mySet);
//Adding values in Bulk
//Add values from myList to mySet maintaing unique constraints
ArrayList<String> myList = new ArrayList<>();
myList.add("Four");
myList.add("Five");
myList.add("Three");
mySet.addAll(myList);
System.out.println(mySet);
//Accessing values using for-each loop
System.out.println("=====for-each========");
for(String element : mySet) {
System.out.println(element);
}
//Accessing values using iterator
System.out.println("=====Iterator========");
Iterator<String> it = mySet.iterator();
while(it.hasNext()) {
System.out.println(it.next());
}
//Accessing values using forEach
System.out.println("Using forEach and Consumer========");
mySet.forEach(System.out::println);
//Clearing
//mySet.clear();
//Check size
System.out.println(mySet.size() + ", " + mySet.isEmpty());
//Contains check -- constant time performance
System.out.println(mySet.contains("Two"));
//Removing elements
mySet.remove("Three");
System.out.println(mySet);
//Retain elements
ArrayList<String> keepThese = new ArrayList<>();
keepThese.add("Four");
keepThese.add("Two");
mySet.retainAll(keepThese);
System.out.println(mySet);
//Converting set to Array
Object[] arr = mySet.toArray();
String[] strArray = mySet.toArray(new String[0]);
//Using Stream
List<String> fromSet = mySet.stream().collect(Collectors.toList());
System.out.println(fromSet);
//----------------------------------------------------------------
//----------------- LinkedHashSet --------------------------------
//----------------------------------------------------------------
//Initializing LinkedHashSet
System.out.println("=========LinkedHashSet==========");
LinkedHashSet<String> lSet = new LinkedHashSet<>();
lSet.add("One");
lSet.add("Two");
lSet.add("Four");
lSet.add("Three");
lSet.add("Three");
System.out.println(lSet);
for (String element : lSet) {
System.out.println(element);
}
}
}
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