Ubuntu Unleashed 2013 Edition: Covering 12.10 and 13.04, Eighth Edition

Variables

All variables in PHP start with a dollar sign ($). Unlike many other languages, PHP does not have different types of variable for integers, floating-point numbers, arrays, or Booleans. They all start with a $, and all are interchangeable. As a result, PHP is a weakly typed language, which means you do not declare a variable as containing a specific type of data; you just use it however you want to.

Save the code in Listing 39.1 into a new file called ubuntu1.php.

Listing 39.1. Testing Types in PHP

<?php  $i = 10;  $j = "10";  $k = "Hello, world";  echo $i + $j;  echo $i + $k;?>

To run that script, bring up a console and browse to where you saved it. Then type this command:

matthew@seymour:~$ php ubuntu1.php

If PHP is installed correctly, ...