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 43.1 into a new file called ubuntu1.php.

LISTING 43.1 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:

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