An Iterator
is an object that can be used to loop through collections, like ArrayList and HashSet.
// Import the ArrayList class and the Iterator class import java.util.ArrayList; import java.util.Iterator; public class Main { public static void main(String[] args) { // Make a collection ArrayList<String> cars = new ArrayList<String>(); cars.add("Volvo"); cars.add("BMW"); cars.add("Ford"); cars.add("Mazda"); // Get the iterator Iterator<String> it = cars.iterator(); // Print the first item System.out.println(it.next()); } } // Outputs: Volvo
Looping Through a Collection
import java.util.ArrayList; import java.util.Iterator; public class Main { public static void main(String[] args) { // Make a collection ArrayList<String> cars = new ArrayList<String>(); cars.add("Volvo"); cars.add("BMW"); cars.add("Ford"); cars.add("Mazda"); // Get the iterator Iterator<String> it = cars.iterator(); // Loop through a collection while(it.hasNext()) { System.out.println(it.next()); } } } // Outputs: Volvo BMW Ford Mazda
Removing Items from a Collection
import java.util.ArrayList; import java.util.Iterator; public class Main { public static void main(String[] args) { ArrayList<Integer> numbers = new ArrayList<Integer>(); numbers.add(12); numbers.add(8); numbers.add(2); numbers.add(23); Iterator<Integer> it = numbers.iterator(); while(it.hasNext()) { Integer i = it.next(); if(i < 10) { it.remove(); } } System.out.println(numbers); } } // Outputs: [12, 23]
标签:Java,Iterator,cars,ArrayList,add,numbers,java From: https://www.cnblogs.com/ShengLiu/p/16930454.html