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 java
//requires either one of these two imports, both work.
import java.util.ArrayList;
//--or--
import java.util.*
ArrayList<DataType> name = new ArrayList<DataType>();
//Defining an arraylist, substitute "DataType" with an Object
//such as Integer, Double, String, etc
//the < > is required
//replace "name" with your name for the arraylistaaraylist java
List<String> list = new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");
list.add("d");
list.add("e");
list.add("f");
//Die Liste zufällig durchmischen
Collections.shuffle(list);
System.out.println(list);
//Die Liste sortieren
Collections.sort(list);
System.out.println(list);
Collections.rotate(list, -1);
System.out.println(list);
//Hier geben wir nur einen Teil (sub) der Liste aus
List<String> sub = list.subList(2, 5);
System.out.println(sub);
Collections.reverse(sub);
System.out.println(sub);
//Hier können wir die Liste manipulieren
ListIterator<String> it = list.listIterator();
while(it.hasNext()){
String str = it.next();
if(str.equals("d"))
it.set("z");
}
while(it.hasPrevious())
System.out.print(it.previous());arraylist in java
Size is dynamic
Only supports objects
not syncronized
array based classCopyright © 2021 Codeinu
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