java arraylist
import java.util.List; //list abstract class
import java.util.ArrayList; //arraylist class
//Object Lists
List l = new ArrayList();
ArrayList a = new ArrayList();
//Specialized List
List<String> l = new ArrayList<String>();
ArrayList<Integer> a = new ArrayList<Integer>();
//only reference data types allowed in brackets <>
//Initial Capacity
List<Double> l = new ArrayList<Double>(5);
//list will start with a capacity of 5
//saves allocation timesarraylist in java
import java.util.ArrayList;
public class ArrayListExample
{
public static void main(String[] args)
{
int num = 14;
// declaring ArrayList with initial size num
ArrayList<Integer> al = new ArrayList<Integer>(num);
// append new element at the end of list
for(int a = 1; a <= num; a++)
{
al.add(a);
}
System.out.println(al);
// remove element at index 7
al.remove(7);
// print ArrayList after deletion
System.out.println(al);
// print elements one by one
for(int a = 0; a < al.size(); a++)
{
System.out.print(al.get(a) + " ");
}
}
}ArrayList
// THIS IS OKAY:
ArrayList arrayList = new ArrayList();arraylist of arraylist
public static void main(String[] args) {
ArrayList<ArrayList<Integer>> outer = new ArrayList<ArrayList<Integer>>();
ArrayList<Integer> inner = new ArrayList<Integer>();
inner.add(100);
inner.add(200);
outer.add(inner); // add first list
inner = new ArrayList<Integer>(inner); // create a new inner list that has the same content as
// the original inner list
outer.add(inner); // add second list
outer.get(0).add(300); // changes only the first inner list
System.out.println(outer);
}arraylist in java
Size is dynamic
Only supports objects
not syncronized
array based classCopyright © 2021 Codeinu
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