The World Wide Web is very much a plain text environment. No matter how rich Web content becomes, HTML lies behind it all. It is no accident, then, that PHP provides many functions with which you can format, investigate, and manipulate strings. Similarly, dates and times are so much a part of everyday life that it becomes easy to work with them without thinking. However, the quirks of the Gregorian calendar can be difficult to work with in programs. Fortunately, PHP provides powerful tools for date arithmetic that make date manipulation an easy task.
In this chapter, you will learn
How to format strings
How to determine the length of a string
How to find a substring within a string
How to break a string down into component parts
How to remove white space from the beginning or end of a string
How to replace substrings
How to change the case of a string
How to acquire the current date and time
How to get information about a date
How to format date information
How to test dates for validity
How to set dates