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From | Nick Cox <n.j.cox@durham.ac.uk> |
To | "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu> |
Subject | st: RE: Dropping Duplicates that Aren't Exactly Duplicates |
Date | Wed, 2 Nov 2011 18:32:07 +0000 |
In general, you are in charge. You get to define what counts as a duplicate you want to drop. Also, you can drop duplicates using any syntax you want that does the job. The -duplicates- command is the way of dealing with duplicates with which I am most familiar. I think you want to duplicates drop id violation, force Nick n.j.cox@durham.ac.uk Lisa Chavez I have data in long file format that has three variables: id, arrdate and violation. Below is an example of a person who has three arrest events (I have separated them with lines). Looking at the first two arrest dates (11mar2004 and 13jan2005) you see that each arrest has three violations and they are exactly the same. I have lots of examples like this one; in all instances I want to drop the last arrest event where this duplication occurs. In the case below, I would want to drop all rows associated with the 13jan2005 arrest event. I'd appreciate any help you can offer. Thanks! Lisa +----------------------------------------------------------------------------------------+ id arrdate violation ---------------------------------------------------------------------------------------- A0000518 11mar2004 Cocaine-Possess Possess Cocaine A0000518 11mar2004 Nonmoving Traffic Viol Drive While Lic Susp Habitual Offender A0000518 11mar2004 Traffic Offense Dui Alcohol Or Drugs 1St Off ---------------------------------------------------------------------------------------- A0000518 13jan2005 Cocaine-Possess Possess Cocaine A0000518 13jan2005 Nonmoving Traffic Viol Drive While Lic Susp Habitual Offender A0000518 13jan2005 Traffic Offense Dui Alcohol Or Drugs 1St Off ---------------------------------------------------------------------------------------- A0000518 27feb2009 Hallucinogen-Sell Schedule Ii +----------------------------------------------------------------------------------------+ * * 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/