PHP: Calculate a math function f(x) in a string

Question

Is it possible to calculate a math function f(x) that in a string. Something like this:

$function = \'2x+3\';
$x = 4;
math_function($function, $x); //Shoud p         


        

Answer 1

My standard answer to this question whenever it crops up:

Don't use eval (especially if the formula contains user input) or reinvent the wheel by writing your own formula parser.

Take a look at the evalMath class on PHPClasses. It should do everything that you want in a nice safe sandbox.