Book Image

PHP 7 Programming Cookbook

By : Doug Bierer
Book Image

PHP 7 Programming Cookbook

By: Doug Bierer

Overview of this book

PHP 7 comes with a myriad of new features and great tools to optimize your code and make your code perform faster than in previous versions. Most importantly, it allows you to maintain high traffic on your websites with low-cost hardware and servers through a multithreading web server. This book demonstrates intermediate to advanced PHP techniques with a focus on PHP 7. Each recipe is designed to solve practical, real-world problems faced by PHP developers like yourself every day. We also cover new ways of writing PHP code made possible only in version 7. In addition, we discuss backward-compatibility breaks and give you plenty of guidance on when and where PHP 5 code needs to be changed to produce the correct results when running under PHP 7. This book also incorporates the latest PHP 7.x features. By the end of the book, you will be equipped with the tools and skills required to deliver efficient applications for your websites and enterprises.
Table of Contents (22 chapters)
PHP 7 Programming Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Using iterators


An iterator is a special type of class that allows you to traverse a container or list. The keyword here is traverse. What this means is that the iterator provides the means to go through a list, but it does not perform the traversal itself.

The SPL provides a rich assortment of generic and specialized iterators designed for different contexts. The ArrayIterator, for example, is designed to allow object-oriented traversal of arrays. The DirectoryIterator is designed for filesystem scanning.

Certain SPL iterators are designed to work with others, and add value. Examples include FilterIterator and LimitIterator. The former gives you the ability to remove unwanted values from the parent iterator. The latter provides a pagination capability whereby you can designate how many items to traverse along with an offset that determines where to start.

Finally, there are a series of recursive iterators, which allow you to repeatedly call the parent iterator. An example would be RecursiveDirectoryIterator...