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| From | Nick Cox <njcoxstata@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: cumulative summation |
| Date | Tue, 26 Feb 2013 10:23:30 +0000 |
Also bysort group year : keep if _n == _N On Tue, Feb 26, 2013 at 9:05 AM, Nick Cox <njcoxstata@gmail.com> wrote: > It works, but does not do what you want. Many solutions, one of which is > > egen nties = max(ties), by(group year) > > See also -help collapse- on your last. > > Nick > > On Tue, Feb 26, 2013 at 8:39 AM, 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/