PHP and MySQL for Dynamic Web Sites: Visual QuickPro Guide

About Numbers

When I began discussing variables, I was explicit in stating that PHP has both integer and floating-point (decimal) number types. In my experience, though, these two types can be classified under the generic title numbers without losing any valuable distinction. Valid number-type variables in PHP can be anything like

• 8

• 3.14

• 10980843985

• -4.2398508

Notice that these values are never quoted—in which case they’d be strings with numeric values—nor do they include commas to indicate thousands. Also, a number is assumed to be positive unless it is preceded by the minus sign (-).

Along with the standard arithmetic operators you can use on numbers (Table 1.1), there are dozens of functions. Two I’ll introduce here are round() and number_format() ...