Core PHP: Variable Variables (2.6)

Variable Variables

With PHP, you can use one variable to specify another variable's name. 

So, a variable variable treats the value of another variable as its name.

For example:

<?php

  $a = 'hello';

  $hello = "Hi!";

  echo $$a;

  // Outputs 'Hi!'

?>

$$a is a variable that is using the value of another variable, $a, as its name. The value of $a is equal to "hello". The resulting variable is $hello, which holds the value "Hi!".