[R] removing observations

Peter Dalgaard p.dalgaard at biostat.ku.dk
Fri Aug 13 16:39:04 CEST 2004

"Justin G. Gardner" <jggardne at uiuc.edu> writes:

> Hello R list.
> I am sure this is an easy question, please forgive my 
> ignorance of R.
> I have a panel data set (25 years) and I would like to break 
> it up by year, and run a few tests.  How is this done in R?  
> In STATA it is quite simple (keep if year =1970).  If someone 
> could give me an example of how to do it for a single year I 
> am sure I could make a little loop to do it for all 25.

There are multiple answers, mostly involving the subset(), tapply(),
or by() functions. So use help(subset), etc.

   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907

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