Iterator and Iterable: the secret weapon of Java collection traversal

php Editor Banana reveals to you the secret weapon of Java collection traversal - Iterator and Iterable. These two interfaces play a vital role in Java. Through them, we can implement collection traversal operations and process data flexibly and efficiently. An in-depth understanding of the principles and usage of these two interfaces will help improve our skills in Java programming. Let's explore their mysteries together!

The Iterable interface defines an iterator() method, which returns an Iterator object that can access the elements in Iterable one by one. The Iterator interface defines three methods: hasNext(), next() and remove(). The hasNext() method returns a Boolean value indicating whether the iterator has a next element. The next() method returns the next element in the iterator. , the remove() method deletes the current element in the iterator.

Iterating through a collection using Iterable and Iterator is very simple, just write a for-each loop. The syntax of the for-each loop is as follows:

for (元素类型 元素变量 : Iterable对象) {
// 对每个元素执行操作
}

For example, the following code uses a for-each loop to traverse a List collection:

List<String> list = new ArrayList<>();
list.add("Java");
list.add("python");
list.add("c++");

for (String language : list) {
System.out.println(language);
}

The output result is:

Java
Python
C++

You can also use Iterator to traverse the collection, just write a while loop. The syntax of the while loop is as follows:

while (迭代器对象.hasNext()) {
// 对当前元素执行操作
迭代器对象.next();
}

For example, the following code uses a while loop to traverse a List collection:

List<String> list = new ArrayList<>();
list.add("Java");
list.add("Python");
list.add("C++");

Iterator<String> iterator = list.iterator();

while (iterator.hasNext()) {
String language = iterator.next();
System.out.println(language);
}

The output result is:

Java
Python
C++

Iterable and Iterator are two very important interfaces in the Java collection framework. They provide a standard way to traverse collections. Both the for-each loop and the while loop can be used to traverse the collection, but the for-each loop is simpler and more convenient. In actual projects, a for-each loop is usually used to traverse the collection.

The above is the detailed content of Iterator and Iterable: the secret weapon of Java collection traversal. For more information, please follow other related articles on the PHP Chinese website!