Re: st: analogue of NODUPKEY

[Richard Williams <Richard.A.Williams.5@nd.edu>]

At 11:05 PM 12/29/2003 -0500, burkom@comcast.net wrote:
> Dear Statalisters,
>
> I am looking for a Stata analogue of a SAS procedure for a certain type of
> duplicate removal.  Suppose a dataset has fields A-J. For all subsets of
> records for which fields A-C are identical, I wish to keep only the first
> record and discard the rest, keeping all fields of the retained records.
> What is the simplest way to do this with Stata commands?
Does the duplicates drop command do what you want? e.g.

duplicates drop a b c, force

From the online help:

"duplicates drop drops all but the first occurrence of each group of 
duplicated observations... force specifies that observations duplicated 
with respect to a named varlist are to be dropped.  The force option is 
required whenever such a varlist is given, as a reminder that information 
may be lost by dropping observations, given that those observations may 
differ on any of the variables not included in varlist."

*
*   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/