Download
1 / 7
70 likes | 194 Vues
This guide provides an in-depth look at Java ArrayLists, highlighting their dynamic characteristics compared to fixed-size arrays. Learn how to declare and initialize an ArrayList, utilize basic operations like adding elements, and explore generic classes with sample codes. Discover how ArrayLists can grow or shrink as needed and see practical examples such as inserting elements at specific positions. Perfect for beginners and developers looking to enhance their understanding of Java collections.
E N D
ArrayLists • Arrays • fixed size • Declare exactly how many you want • ArrayList • Dynamic • Variable length • Can grow and shrink • Generic class
ArrayList<E> • E – element • ArrayList<String> • ArrayList<Point>
Create an empty ArrayList import java.util.*; public class ArrayL { static Scanner console = new Scanner(System.in); public static void main (String args[]) { ArrayList<String> list = new ArrayList<String>(); System.out.println("List = " + list); } } > run ArrayL List = []
Basic ArrayList operations import java.util.*; public class ArrayL { static Scanner console = new Scanner(System.in); public static void main (String args[]) { ArrayList<String> list = new ArrayList<String>(); list.add("Apple"); //new values are added to the end list.add("Orange"); System.out.println("List = " + list); } }
import java.util.*; public class ArrayL { static Scanner console = new Scanner(System.in); public static void main (String args[]) { ArrayList<String> list = new ArrayList<String>(); System.out.println("List = " + list); list.add("Apple"); list.add("Orange"); System.out.println("List = " + list); list.add(1,"Broccoli"); System.out.println("List = " + list); } } List = [] List = [Apple, Orange] List = [Apple, Broccoli, Orange]
