st: spell variable according to a criteria

[Abhimanyu Arora <abhimanyu.arora1987@gmail.com>]

Dear statalist

I have a (monthly) time indicator and a variable 'stretch'  that
identifies the spell of an event. I need to create a dummy in case the
event took place or not.
Currently event=1 for the start of the event (an missing for the
rest). If stretch==1, event should equal 1 for the next time period.
If stretch =2 event=1 for 2 more time periods (besides the starting
time).

I know that stretch ranges from 1 to 18 (but may not have the values
in between).

When I try without using the following loop (putting in the numbers
manually that is), it seems OK, But with the following loop things
aren't quite right.

local i=0
while `i'< 18 {
bys panel_identifier:replace event=1 if  stretch[_n-(`i'+1)]>`i' &
stretch[_n-(`i'+1)]!=. & event==.
sort panel_id time
local ++i
}

Where does the mistake lie?
Cheers
Abhimanyu
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/