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From | James Bernard <jamesstatalist@gmail.com> |
To | statalist@hsphsun2.harvard.edu |
Subject | Re: st: cumulative summation |
Date | Tue, 26 Feb 2013 17:03:15 +0800 |
Hi Nick, Or, I am thinking about an easier option: For me the first observation is not useful, so I want the second one for firm A in year 1990.For firm A in year 1991, I have only one observation and I need it. For B in year 1990 I want the observation where ties is equal to 3. I don't want the other two cases of Firm B in year 1990. So, I want them dropped from my dataset. Thanks, james Firm Year ties >>> ----------- ---------- ------- >>> A 1990 1 >>> A 1990 2 >>> A 1991 1 >>> B 1990 0 >>> B 1990 1 >>> B 1990 3 >>> C 1990 0 >>> C 1991 0 >>> C 1992 0 >>> On Tue, Feb 26, 2013 at 4:39 PM, James Bernard <jamesstatalist@gmail.com> wrote: > Thanks Nick, > > I have missing values in my list, so it seems that the command is not > working, because it sets many of the values to . (missing). > > I gave you the simplifies version. In fact, I am using loops and > macros to do this > > Then, instead would it be possible to write a comand that can detect > that for firm A in 1990, 2 is the larger one. > > Alternatively, would it be possible to ask the program to keep only > the last observation of every group (a group defined by firm and year) > > Thanks a gain, > James > > > On Tue, Feb 26, 2013 at 3:49 PM, Nick Cox <njcoxstata@gmail.com> wrote: >> bysort firm year (ties) : replace ties = ties[_N] >> >> Nick >> >> On Tue, Feb 26, 2013 at 7:08 AM, James Bernard <jamesstatalist@gmail.com> wrote: >> >>> I have used the sum function to calculate a variable in a panel data. >>> >>> Firm Year ties >>> ----------- ---------- ------- >>> A 1990 1 >>> A 1990 2 >>> A 1991 1 >>> B 1990 0 >>> B 1990 1 >>> B 1990 3 >>> C 1990 0 >>> C 1991 0 >>> C 1992 0 >>> >>> The issue is that the variable ties which is the number of ties a firm >>> has formed in a year is a cumulative sum of something and, therefore, >>> for a company like A the final number of ties in year 1990 should be >>> 2. I need the program to write the same number (final value of the >>> cumulative sum) instead of 1. >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/faqs/resources/statalist-faq/ >> * http://www.ats.ucla.edu/stat/stata/ * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/