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
     $hello = "Hi!";
     $a = 'hello';
     echo $$a; 
// output "Hi!"
?>
by Guram Azarashvili
2 years ago
PHP
PHP official doc
0
Pro tip: use ```triple backticks around text``` to write in code fences