Converting between List and Array is a very common operation in Java.
The best and easiest way to convert a List into an Array in Java is to use the .toArray[] method.
Likewise, we can convert back a List to Array using the Arrays.asList[] method.
The examples below show how to convert List of String and List of Integers to their Array equivalents.
Convert List to Array of String
import java.util.ArrayList; import java.util.List; public class ConvertArrayListToArray { public static void main[String[] args] { List itemList = new ArrayList[]; itemList.add["item1"]; itemList.add["item2"]; itemList.add["item3"]; String[] itemsArray = new String[itemList.size[]]; itemsArray = itemList.toArray[itemsArray]; for[String s : itemsArray] System.out.println[s]; } }We can use the same approach to convert List of Integers to Array of Integers, for example:
Related:
- How to loop through an ArrayList in Java
- How to remove duplicates from a list
- How to compare two ArrayLists in Java
Convert List to Array of Integers
import java.util.ArrayList; import java.util.List; public class ConvertArrayListToArray { public static void main[String[] args] { List intList = new ArrayList[]; intList.add[10]; intList.add[20]; intList.add[30]; Integer[] intArray = new Integer[intList.size[]]; intArray = intList.toArray[intArray]; for[Integer i : intArray] System.out.println[i]; } }Convert String Array to List
You can also convert an Array back to a List. To do this, we use Arrays.asList[]. For example:
import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class ConvertArrayToList { public static void main[String[] args] { String[] stringArray = {"item 1", "item 2", "item 3", "item 4"}; List stringList = new ArrayList[Arrays.asList[stringArray]]; for [String listItem : stringList] { System.out.println[listItem]; } } }Share this on: Twitter LinkedIn