Use foreach loop to assign postdata variable

Question

I wonder if I can use foreach to optimize my code and avoid mistakes.

I have to set variable like that from postdata:

$a2 = $postdata->a2;    
$a3 = $postdata->a3;        
$a4 = $postdata->a4;

and so on...

I forgot one line, it cause trooble in my treatment.

I thought a code like that, but, I'm no sure it will works:

foreach($postdata as $key => $value) {  
            $"a2, a3, a4,..." = $postdata->"a2, a3, a4,...";
}

Thanks for helping me ;)