[Zope] HOW TO COUNT VARIABLE WITH <DTML-IN>

[Mike Doanh Tran]

How do i count the value of a variable inside of <dtml-in>
I want to count not just the occurence of the  variable but the
value of that variable also. For Example i have a variable name "weight":

<dtml-in getQuery>
  <dtml-var count-weight>
</dtml-in getQuery>

<dtml-var count-weight> will give me a total number of occurence for the 
variable weight.  What i want to do is count the value of weight.

if weight=1 then count how many 1 there are
if weight=2 then count how many 2 there are
and so on ....

I've tried to used <dtml-let> to initial a variable but can't do it.
Does anyone have any suggesstions on how i can do this using DTML?

Thanks for any suggestion,

-- 
Mike