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Re: st: RE: Dropping Duplicates that Aren't Exactly Duplicates


From   Lisa Chavez <lchavez@law.berkeley.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Dropping Duplicates that Aren't Exactly Duplicates
Date   Wed, 02 Nov 2011 11:50:23 -0700

Thank you for your reply. I tried that before but what happened was that I ended up dropping rows that I didn't want to drop. For example, say a person has three arrest events with four violations each. The first two arrest events have the exact same violations and the third arrest has two violations but ONE of violations in the third arrest was the same as one violation in one of the first two arrest events. The result is that I dropped out a single violation out of the third arrest event (and I wanted the third arrest untouched). --Lisa

On 11/2/2011 11:32 AM, Nick Cox wrote:
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
+----------------------------------------------------------------------------------------+



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