Variable variables are one of my favorite things about PHP. PHP allows you to use a variable to reference another variable. This comes in exceptionally handy when you need to create variable names dynamically:
$variable = 'This is my variable'; $var = 'variable'; echo $$var;
Let’s say you have you have a variable that uses another variable as part of the name:
$array = range(1, 100); $format_json = json_encode($array); $format_serial = serialize($array); $format = 'json'; $variable = 'format_' . $format; echo $$variable;
Granted this is a very simple example to demonstrate the functionality. Real world usage could end up being more complex and really show off the power of variable variables.