array list operatoins useful and remember
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
public class ArrayListExample {
public static void main(String[] args) {
// Create an ArrayList and add elements
List<String> arrayList = new ArrayList<>();
arrayList.add("Apple");
arrayList.add("Banana");
arrayList.add("Cherry");
arrayList.add("Date");
// 1. Accessing Elements
System.out.println("1. Accessing Elements:");
String firstElement = arrayList.get(0);
System.out.println("First element: " + firstElement);
// 2. Modifying Elements
System.out.println("\n2. Modifying Elements:");
arrayList.set(1, "Blueberry");
System.out.println("Updated ArrayList: " + arrayList);
// 3. Adding Elements
System.out.println("\n3. Adding Elements:");
arrayList.add("Fig");
System.out.println("After adding 'Fig': " + arrayList);
// 4. Removing Elements
System.out.println("\n4. Removing Elements:");
arrayList.remove(2); // Remove by index
System.out.println("After removing element at index 2: " + arrayList);
arrayList.remove("Date"); // Remove by value
System.out.println("After removing 'Date': " + arrayList);
// 5. Checking if an Element Exists
System.out.println("\n5. Checking if an Element Exists:");
boolean containsBanana = arrayList.contains("Banana");
System.out.println("Contains 'Banana'? " + containsBanana);
// 6. Checking if ArrayList is Empty
System.out.println("\n6. Checking if ArrayList is Empty:");
boolean isEmpty = arrayList.isEmpty();
System.out.println("Is the ArrayList empty? " + isEmpty);
// 7. Getting the Size
System.out.println("\n7. Getting the Size:");
int size = arrayList.size();
System.out.println("Size of ArrayList: " + size);
// 8. Iterating Over ArrayList
System.out.println("\n8. Iterating Over ArrayList:");
for (String fruit : arrayList) {
System.out.println(fruit);
}
// 9. Sorting
System.out.println("\n9. Sorting:");
Collections.sort(arrayList);
System.out.println("Sorted ArrayList: " + arrayList);
// 10. Clearing the ArrayList
System.out.println("\n10. Clearing the ArrayList:");
arrayList.clear();
System.out.println("Cleared ArrayList: " + arrayList);
// 11. Converting ArrayList to Array
System.out.println("\n11. Converting ArrayList to Array:");
String[] array = arrayList.toArray(new String[0]);
// 12. Checking if ArrayList Contains All Elements of Another Collection
System.out.println("\n12. Checking if ArrayList Contains All Elements of Another Collection:");
List<String> subList = new ArrayList<>();
subList.add("Apple");
subList.add("Cherry");
boolean containsAll = arrayList.containsAll(subList);
System.out.println("Contains all elements of 'subList'? " + containsAll);
}
}
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import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.ListIterator;
public class ArrayListMoreExamples {
public static void main(String[] args) {
// Create an ArrayList and add elements
List<String> arrayList = new ArrayList<>();
arrayList.add("Apple");
arrayList.add("Banana");
arrayList.add("Cherry");
arrayList.add("Date");
// 11. Getting an Element by Index
System.out.println("11. Getting an Element by Index:");
String thirdElement = arrayList.get(2);
System.out.println("Third element: " + thirdElement);
// 12. Adding Elements at a Specific Index
System.out.println("\n12. Adding Elements at a Specific Index:");
arrayList.add(1, "Grapes");
System.out.println("After adding 'Grapes' at index 1: " + arrayList);
// 13. Removing All Occurrences of an Element
System.out.println("\n13. Removing All Occurrences of an Element:");
arrayList.add("Banana"); // Add a duplicate
arrayList.removeAll(Collections.singleton("Banana"));
System.out.println("After removing all 'Banana' occurrences: " + arrayList);
// 14. Checking if an ArrayList Contains a Sublist
System.out.println("\n14. Checking if an ArrayList Contains a Sublist:");
List<String> subList = new ArrayList<>();
subList.add("Cherry");
subList.add("Date");
boolean containsSubList = arrayList.containsAll(subList);
System.out.println("Contains all elements of 'subList'? " + containsSubList);
// 15. Reversing the ArrayList
System.out.println("\n15. Reversing the ArrayList:");
Collections.reverse(arrayList);
System.out.println("Reversed ArrayList: " + arrayList);
// 16. Getting the Index of the First Occurrence of an Element
System.out.println("\n16. Getting the Index of the First Occurrence of an Element:");
int indexOfCherry = arrayList.indexOf("Cherry");
System.out.println("Index of 'Cherry': " + indexOfCherry);
// 17. Getting the Last Index of an Element
System.out.println("\n17. Getting the Last Index of an Element:");
int lastIndexOfDate = arrayList.lastIndexOf("Date");
System.out.println("Last index of 'Date': " + lastIndexOfDate);
// 18. List Iterator for Bidirectional Traversal
System.out.println("\n18. List Iterator for Bidirectional Traversal:");
ListIterator<String> listIterator = arrayList.listIterator();
while (listIterator.hasNext()) {
System.out.print(listIterator.next() + " ");
}
System.out.println();
// 19. Checking if the ArrayList Contains No Duplicates
System.out.println("\n19. Checking if the ArrayList Contains No Duplicates:");
boolean hasDuplicates = arrayList.size() != new ArrayList<>(new HashSet<>(arrayList)).size();
System.out.println("Contains duplicates? " + hasDuplicates);
// 20. Removing Elements That Satisfy a Condition
System.out.println("\n20. Removing Elements That Satisfy a Condition:");
arrayList.removeIf(element -> element.startsWith("C"));
System.out.println("After removing elements starting with 'C': " + arrayList);
}
}