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Java - how to use Iterator with ArrayList
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In this article, we would like to show you how to use iterator with ArrayList in Java.
Quick solution:
Introduction
Iterator is an object that can be used to loop through collections. In this article, we will focus on the ArrayList collection and loop through it.
Create iterator
To use Iterator, the first thing we need to do is obtain it from a Collection. To do so, we use iterator[] method in the following way:
List myArrayList = ... Iterator myIterator = myArrayList.iterator[];Iterator methods
- hasNext[] -checksif there is at least one element left to iterate over, it's commonlyused as a condition in while loops.
- next[] -stepsover the next element and obtainsit.
Practical example
In this example, we create an iterator for letters ArrayList to display all the elements in the proper order.
import java.util.*; public class Example { public static void main[String[] args] { List letters = new ArrayList[]; letters.add["A"]; letters.add["B"]; letters.add["C"]; // create an iterator Iterator myIterator = letters.iterator[]; // display values after iterating through the ArrayList System.out.println["The iterator values of the list are: "]; while [myIterator.hasNext[]] { System.out.print[myIterator.next[] + " "]; } } }Output:
The iterator values of the list are: A B C