9.1. Introduction

The previous chapters covered the most widely used extensions. This chapter presents other valuable mainstream extensions. The first section describes a group of functions that are part of the core PHP, not a separate extension. The remaining sections discuss several popular and useful extensions that are not part of the core PHP.

After you finish reading this chapter, you will have learned

• Open, read, and write local and remote files

• Communicate with processes and programs

• Work with streams

• Match text, validate input text, replace text, split text, and other text manipulations using regular expressions with PHP functions

• Handle parsing and formatting dates and times, including DST issues

• Build images with the GD extension

• Extract meta information from digital images with the Exif extension

• Convert between single- and multi-byte character sets