Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

RE: st: identify group of observations


From   "Nick Cox" <n.j.cox@durham.ac.uk>
To   <statalist@hsphsun2.harvard.edu>
Subject   RE: st: identify group of observations
Date   Thu, 29 Apr 2004 11:32:06 +0100

Or just 

gen grp = sum(flag == "01") 

Nick 
n.j.cox@durham.ac.uk 

Doug Owens replied to MITRA PINAKI 

> I have a data set where I need to group observations. The 
> identifying flag
> is two character string which can be either "01" or "02". Each "01"
> observation is followed by "02", so the flag for the first 
> obs is "01" and
> the very next one's is "02". But these are always not in 
> pair; order can be
> "01" and "02"; "01", "02", "02"; "01", "02", "02, "02" and 
> so on. All the
> "02" obs. followed by "01" belong to one group. Is there 
> any way I can
> generate an identifier that indicates these groups?
> 
Assuming you want to create grp like:
Flag  grp
 01      1
 02      1
 01      2
 02      2
 02      2
 01      3
 02      3
 02      3
 02      3
 
Then you can just
gen grp = flag=="01"
replace grp = sum(grp)

*
*   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/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index