Java Iterator and Iterable: The key to collection traversal, demystified

Introduction to Iterator

Java Iterator and Iterable are very important concepts in Java programming. They provide a convenient way to traverse collections. PHP editor Apple will unveil the mystery of Iterator and Iterable, and deeply explore their application and implementation principles in Java programming. By learning Iterator and Iterable, developers can operate various collections more flexibly and efficiently, improving the quality and efficiency of their code. Let us uncover the mysteries of these two concepts and discover the key to set traversal!

Demo code:

List<String> list = new ArrayList<>();
list.add("one");
list.add("two");
list.add("three");

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

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

In the above code, we first create a stringlist, and then use the iterator() method to obtain the Iterator of the list. Next, we use a while loop to iterate through the elements in the list and use the next() method to get each element. Finally, we use the println() method to print each element.

Introduction to Iterable

Iterable is another interface in Java for traversing collections. It provides a unified way to traverse different collection types. You can use Iterable to iterate over collection types such as List, Set, and Map.

Demo code:

Iterable<String> iterable = list;

for (String element : iterable) {
System.out.println(element);
}

In the above code, we first convert the list into an Iterable type. Then, we use a for-each loop to iterate over the elements in the Iterable. The for-each loop automatically calls the iterator() method of Iterable to obtain the Iterator, and uses the next() method to obtain each element. Finally, we use the println() method to print each element.

The difference between Iterator and Iterable

Iterator and Iterable are two important interfaces in Java for traversing collections. The main differences between them are:

• Iterator is a one-way iterator, which means you can only traverse the elements in the collection forward.
• Iterable is a bidirectional iterator, which means you can traverse the elements in the collection forward and backward.

When to use Iterator and Iterable

In most cases, you should use Iterable to traverse collections. Iterable provides a more unified and convenient way to iterate over different collection types. You only

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