st: Ranking timed data

[Sascha Robert <sascha.robert@iew.unizh.ch>]

Hi

I applogize for this newbie question in advance.
My data looking like this

time    id    var
1        1    19.5
1        2    20.7
1        3    15.0
2        1    16.5
2        2    21.7
2        3    17.0
...

Now I would like to generate a variable 'rank' for each value of 'time' 
representing the ordinal number of th value 'var':

time    id    var    rank
1        1    19.5    2
1        2    20.7    1
1        3    15.0    3
2        1    16.5    3
2        2    21.7    1
2        3    17.0    2
...

. recode does not seem to work, because 'var' changes to a great extent 
over time.

Any hints? Thankyou
Sascha

--
***** sascha robert | mailto: sascha.robert@iew.unizh.ch *****
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/