Question

lets assume that i have function named printuser()

now if i have string like

$myFunction = 'printuser()';

how i can run this string as function ? so it should do the printuser() function

Answer 1

If you just want $myFunction to specify which function to run, you can do something like

$myFunction = 'printuser';
$myFunction();

This is called a “variable function“, and is slightly less dangerous than eval. (You can call any existing function, but you can’t run arbitrary code.)

Be warned, though: if printuser doesn’t exist, the script will die. You might consider checking for the function’s existence before calling it.

$myFunction = 'printuser';
if (function_exists($myFunction))
    $myFunction();
else
    throw new BadFunctionCallException("Function '$myFunction' doesn't exist");

Replace the throw with whatever you want to do if the function isn’t there. That’s just an example.