Variable Variables Tutorial in WordPress

variable-variables.php

<?php

$variable_name = 'post_id';
$$variable_name = 10;

//* Or use curly braces to specify exactly which variable is being used
//* as the variable variable, i.e. variable name
${$variable_name} = 10;

/**
 * Think of it like this:
 * 
 * 1.   $variable_name holds the variable name that you will use "later"
 *      to access or create a variable.
 * 2.   In ${$variable_name}, replace what is in the curly braces with
 *      the "assignment" in the variable $variable_name, which here is 'post_id'.
 */

//* Now let's see what assignments were made
echo '$$variable_name = ';
var_dump( $$variable_name );

//* Notice that I did not declare the variable $post_id;
//* however, PHP did create it...dynamically.
echo '$post_id = ';
var_dump( $post_id );