Create a class based on a string and pass the constructor arguments at the same time

Question

I have a piece of code that basically creates an instance of a class on-the-fly:

$class = 'user';
return new $class;

The challenge is that I have the constructor's arguments in an array format and they're obviously different from class to class -- so there is no pattern at all that I can make anything on top of that. There are some workarounds here to extract these arguments from the array and pass it all through in a way like this:

$args = array( 'one', 'two' );
// some code to generate $arg1, $arg2, etc.
return new $class( $arg1, $arg2 );

However, I really prefer to do it in a smarter way. As far as I can see there is no way to make use of call_user_func and call_user_func_array unless I forget about the constructor and initialize it after instantiation.

Update

Basically I'm looking for something like this:

return magic_func( 'className', array('one', 'two') );

deceze · Accepted Answer · 2014-02-28 08:41:45Z

6

return (new ReflectionClass($class))->newInstanceArgs($args);

See http://php.net/manual/en/reflectionclass.newinstanceargs.php

answered Feb 28, 2014 at 8:41

deceze♦

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1 Comment

Mahdi Over a year ago

Thanks! for some reason I got a syntax error unexpected T_OBJECT_OPERATOR, however when I did break it down into two statements -- like in the manual, then it worked out as expected!

Black Mantha · Accepted Answer · 2025-10-01 16:09:16Z

3

A newer syntax, using variable-length argument lists:

return new $class(...$args);

answered Oct 1 at 16:09

Black Mantha

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