st: Stacking data per day

[Julian Runge <rungejuq@hu-berlin.de>]

Hello everybody!

I am encountering a problem when trying to stack data in daily
intervals. I guess this is just a basic problem, but after quite some
effort I haven't been able to figure out how to do it. My data set
contains profits/losses (variable pl) from a permanently ongoing
trading game. That means, there can be several profit/loss events on
the same day and even in the same minute (the time variable contains
minutes, but not seconds). So, when I try to assign the data set a
panel data structure, this is denied due to "repeated time values
within panel". I wish to calculate the daily sums of pl. I tried to
use the "stack" command, but wasn't able to formulate an if-expression
telling Stata to stack the data for each day.

Can anybody help me with that?

Thanks, best,
Julian

--
Julian Runge, B.Sc.
Humboldt University Berlin
M.Sc. Economics and Management Science
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