Java Iterator and Iterable: Exploring the Art of Java Collection Traversal

Java Iterator and Iterable: Exploring the art of collection traversal in Java. In Java programming, Iterator and Iterable are important interfaces for traversing collection elements. They provide a flexible and efficient way to access and manipulate elements in a collection. This article will delve into the principles and usage of the Iterator and Iterable interfaces to help readers better understand the technical details of Java collection traversal. PHP editor Banana will unveil the mystery of this "art" for everyone, allowing you to easily master the essence of set traversal.

1. Iterator interface

The Iterator interface defines methods for traversing collection elements, including hasNext() and next(). The hasNext() method is used to check whether there are more elements in the collection, and the next() method is used to get the next element.

import java.util.Iterator;

public class IteratorDemo {

public static void main(String[] args) {
// 创建一个 ArrayList 集合
ArrayList<String> list = new ArrayList<>();

// 添加一些元素到集合中
list.add("Java");
list.add("python");
list.add("c++");
list.add("C#");

// 获取集合的 Iterator 对象
Iterator<String> iterator = list.iterator();

// 遍历集合元素
while (iterator.hasNext()) {
String element = iterator.next();
System.out.println(element);
}
}
}

Output:

import java.util.Iterable;

public class IterableDemo implements Iterable<String> {

private String[] elements = {"Java", "Python", "C++", "C#"};

@Override
public Iterator<String> iterator() {
return new Iterator<String>() {

private int index = 0;

@Override
public boolean hasNext() {
return index < elements.length;
}

@Override
public String next() {
return elements[index++];
}
};
}

public static void main(String[] args) {
// 创建一个 IterableDemo 对象
IterableDemo iterableDemo = new IterableDemo();

// 遍历集合元素
for (String element : iterableDemo) {
System.out.println(element);
}
}
}

Output:

import java.util.ArrayList;
import java.util.Iterator;

public class IteratorIterableDemo {

public static void main(String[] args) {
// 创建一个 ArrayList 集合
ArrayList<String> list = new ArrayList<>();

// 添加一些元素到集合中
list.add("Java");
list.add("Python");
list.add("C++");
list.add("C#");

// 使用 Iterator 遍历集合元素
Iterator<String> iterator = list.iterator();
while (iterator.hasNext()) {
String element = iterator.next();
System.out.println(element);
}

// 使用 for-each 循环遍历集合元素
for (String element : list) {
System.out.println(element);
}
}
}

Output:

Java
Python
C++
C#
Java
Python
C++
C#

4 Conclusion

Iterator and Iterable are two important interfaces in the Java collection framework for traversing collection elements. Iterator provides methods for traversing collection elements, while Iterable represents a traversable collection. The two work together to effectively implement collection elements. traversal and operations.

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