need help translating a PHP for statement to python

[Dang Griffith]

On Sat, 10 Jan 2004 20:22:18 +1100, "Eli Pollak" <none at none.com>
wrote:

>Haha ... you must be originally a perl coder. Who else writes attricious
>code like this
>    if ($bar = (($x_ar[$x] -= $prd + $bar) < 0))

Any C programmer worth his salt.  I miss those days.  Sort of.
    --dang