How to create object from String?

Question

I tried the code below:

$dyn = "new ". $className . "(" .$param1 . ", ". $param2 . ");";
$obj = eval($dyn);

It compiles but it's null.

How can you instance object in PHP dynamicaly?

Answer 1

$class = 'ClassName';
$obj = new $class($arg1, $arg2);

Answer 2

If you really want to use eval - which chances are you shouldn't if you're this new to PHP ;) - you'd do something more like...

$dyn = "new ". $className . "(" .$param1 . ", ". $param2 . ");";
eval("\$obj = $dyn");

Answer 3

What are you actually trying to accomplish? eval would work, but its probably not a very good idea.

What you might want to do is implement a factory for your objects that take a string defining what class to load, and an optional array for the constructors parameters