PHP defines 8 different variable types.  These are outlined here for your quick reference.  Be familiar with each of the different types and how they may be used in your programming.

===== Scalar Types =====

^ Data Type ^ Description ^
| **''Boolean''** | A logical datatype with only two distinct possible values: **''true''** and **''false''** |
| **''Integer''** | A numeric value in the form of a whole number.  A whole number has no fractional parts (or decimal point). |
| **''Float''** | A floating point or real number.  This number is in the format **''-35.2357''** |
| **''String''** | A string is an ordered sequence of characters.  A character may be any unicode character your computer may display. |

===== Compound Types =====

^ Data Type ^ Description ^
| **''Array''** | An array is an indexed list of items.  In PHP, arrays may be indexed by number (a regular array) or by strings (an associative array) |
| **''Object''** | An object is an instance of a class that contains member variables and methods.  Data and method implementations are encapsulated and hidden from the user to simplify development and maintain the integrity of the system. |

===== Special Types =====

^ Data Type ^ Description ^
| **''Resource''** | A special operating system specific piece of data.  This may correspond to a database connection, an image resource or a filesystem context |
| **''Null''** | Null is a special value that is assigned to a variable to indicate that the variable holds no valid data. |