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From |
emanuele mazzini <madsoenistata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Loop year variable |

Date |
Mon, 22 Oct 2012 11:44:21 +0200 |

Ops, sorry about that. You are right, it worked now! Thank you very much for help! Kind Regards, E.M. 2012/10/22 Nick Cox <njcoxstata@gmail.com>: > You did not do what I suggested. > > I suggested > > bysort iso_o iso_d (year) : > by iso_o iso_d : > > but your code is > > bysort iso_o iso_d year : > by iso_o iso_d year : > > That's quite wrong for your problem. Study the documentation for -by:- > if you don't see why. > > By the way, the code might be slightly better as > > bysort iso_o iso_d (year FT_A) : > by iso_o iso_d : > > Nick > > On Mon, Oct 22, 2012 at 10:05 AM, emanuele mazzini > <madsoenistata@gmail.com> wrote: >> Many thanks Nick. That worked well in the subsample I showed you. >> However, in my general sample I do not get as many as changes as I >> thought. >> >> I typed the following: >> >> bysort iso_o iso_d year: gen date_won = year if FT_A > FT_B | FT_A<FT_B >> by iso_o iso_d year: replace date_won = date_won[_n-1] if missing(date_w) >> >> that seems correct to me, but I only obtain 14 real changes, that are >> a way too low. That seems actually very strange to me, why I can't get >> the replace? May it be due to the structure of the dataset? I mean, >> even though it is not a panel in the proper sense, because I can have >> more than 1 observation per year, that should not be a matter of >> concern, because the date_won variable always takes the same value, >> doesn't it? >> >> Many thanks in advance for your help, >> >> Regards, >> >> Emanuele. >> >> >> >> 2012/10/22 Nick Cox <njcoxstata@gmail.com>: >>> See for technique here >>> >>> FAQ . . . . . . . . . . . . . . . . . . . . . . . Replacing missing values >>> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox >>> 2/03 How can I replace missing values with previous or >>> following nonmissing values? >>> http://www.stata.com/support/faqs/data/missing.html >>> >>> bysort iso_o iso_d (year) : gen datewon = year if !missing(FT_A, FT_B) >>> & FT_A > FT_B >>> by iso_o iso_d : replace datewon = datewon[_n-1] if missing(datewon) >>> gen yrs_won = date - datewon >>> >>> Nick >>> >>> On Sun, Oct 21, 2012 at 10:37 PM, emanuele mazzini >>> <madsoenistata@gmail.com> wrote: >>>> Ok, let's ignore this additional issue for the moment. I can be >>>> clearer I guess with the following example: >>>> >>>> +---------------------------------------------------------------------+ >>>> | year iso_o iso_d team_A team_B FT_A FT_B date_won | >>>> |---------------------------------------------------------------------| >>>> 1. | 1982 ITA DEU Italy Germany FR 3 1 1982 | >>>> 2. | 1983 ITA DEU . . . | >>>> 3. | 1984 ITA DEU . . . | >>>> 4. | 1985 ITA DEU . . . | >>>> 5. | 1986 ITA DEU . . . | >>>> |---------------------------------------------------------------------| >>>> 6. | 1987 ITA DEU . . . | >>>> 7. | 1988 ITA DEU . . . | >>>> 8. | 1989 ITA DEU . . . | >>>> 9. | 1990 ITA DEU . . . | >>>> 10. | 1991 ITA DEU . . . | >>>> |---------------------------------------------------------------------| >>>> 11. | 1992 ITA DEU . . . | >>>> 12. | 1993 ITA DEU . . . | >>>> 13. | 1994 ITA DEU . . . | >>>> 14. | 1995 ITA DEU . . . | >>>> +---------------------------------------------------------------------+ >>>> >>>> As you can see, the variable date_won is =1982 only for the year in >>>> which the match was played. Now, I would like to generate a new >>>> variable that would tell me how many years have gone by since Italy's >>>> last won (e.g, =0 for 1982, =1 for 1983, =2 for 1984, etc.). >>>> As I said, I tried with: gen yrs_won=year-date_won but this is the result: >>>> >>>> +---------+ >>>> | yrs_won | >>>> |---------| >>>> 1. | 0 | >>>> 2. | . | >>>> 3. | . | >>>> 4. | . | >>>> 5. | . | >>>> |---------| >>>> 6. | . | >>>> 7. | . | >>>> 8. | . | >>>> 9. | . | >>>> 10. | . | >>>> |---------| >>>> 11. | . | >>>> 12. | . | >>>> 13. | . | >>>> 14. | . | >>>> +---------+ >>>> >>>> As you can see, such command doesn't produce the expected result. That >>>> explains why I was looking for a way to expand the value of date_won >>>> for all cells. I thought that was the reason for the command not to >>>> work. Do you have any suggestion for overcoming my problem? >>>> >>>> Thank you in advance, >>>> >>>> Regards, >>>> >>>> E.M. >>>> >>>> >>>> >>>> >>>> 2012/10/21 Nick Cox <njcoxstata@gmail.com>: >>>>> I gathered from your original posting that you had yearly data. I >>>>> understand that matches may be more frequent than yearly, but I can't >>>>> advise further without seeing what your data look like as the trade >>>>> data and match data are not obviously compatible. >>>>> >>>>> Nick >>>>> >>>>> On Sun, Oct 21, 2012 at 1:00 PM, emanuele mazzini >>>>> <madsoenistata@gmail.com> wrote: >>>>>> Dear Mr Cox, >>>>>> >>>>>> thank you for your reply. The point, however, is that I cannot declare >>>>>> my dataset to be time-series (how would like but I cannot) due to the >>>>>> fact that some matches may take place once, twice or even more times >>>>>> in the same year. That is why I was looking form a manual command. I >>>>>> may better handle this first? And how can I do that in your opinion? >>> >>> >>> 2012/10/21 Nick Cox <njcoxstata@gmail.com>: >>>>>>> This should yield to a treatment in terms of spells in the sense of >>>>>>> -tsspell- (SSC) and of >>>>>>> >>>>>>> SJ-7-2 dm0029 . . . . . . . . . . . . . . Speaking Stata: Identifying spells >>>>>>> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. J. Cox >>>>>>> Q2/07 SJ 7(2):249--265 (no commands) >>>>>>> shows how to handle spells with complete control over >>>>>>> spell specification >>>>>>> >>>>>>> Look at -tsspell- first; it is self-contained. That is, your panels >>>>>>> are defined by country pairs (dyads) and the start of a spell is >>>>>>> defined by a match taking place (or a particular result; I don't >>>>>>> follow exactly what you want, e.g what about draws?). Then a variable >>>>>>> defined by -tsspell- gives you sequence in spell. You may need to >>>>>>> subtract 1. >>>>>>> >>>>>>> I don't see that loops are needed. >>>>>>> >>>>>>> Nick >>>>>>> >>>>>>> On Sun, Oct 21, 2012 at 12:07 PM, emanuele mazzini >>>>>>> <madsoenistata@gmail.com> wrote: >>>>>>> >>>>>>>> I am not a new Stata user, but I have to admit I still encounter some >>>>>>>> problems with writing loops. A loop may not be the solution to the >>>>>>>> issue I am going to describe, but I thought it is tough. >>>>>>>> >>>>>>>> I do have a dataset where I have country-pair trade observations for >>>>>>>> years 1950-2006 as well as another information, which is football >>>>>>>> match result for some dyads. I therefore need to generate a variable >>>>>>>> that indicates how many years are passed since the last won/lost of a >>>>>>>> country versus another. Suppose FT_A and FT_B are the final results >>>>>>>> for team A and B. I thought to generate a variable as follows: >>>>>>>> >>>>>>>> gen int date_won=year if FT_A>FT_B | FT_A<FT_B >>>>>>>> >>>>>>>> in order to get a variable that is = year for every observation I have >>>>>>>> information about, which reports the year of the won/loss. I then >>>>>>>> thought to generate another variable (let's say yrs_won) to tell me >>>>>>>> how many years have gone by as follows: >>>>>>>> >>>>>>>> gen int yrs_won=year-date_won >>>>>>>> >>>>>>>> Unfortunately, I do not get what I want: the only value yrs_won >>>>>>>> assumes is 0, but for all years from 1983 until 2006 I would like it >>>>>>>> to be 1, 2,3 and so on. >>>>>>>> >>>>>>>> At the beginning I didn't realize the problem, now it may be occur due >>>>>>>> to the fact that date_won = year only for the year in which the match >>>>>>>> was played. I guess I need to do something such as writing a loop to >>>>>>>> let it spread over all cells of such variable, but I don't really know >>>>>>>> how to make it. Does anyone of you has any suggestion? >>> * >>> * 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/ > * > * 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/

**References**:**st: Loop year variable***From:*emanuele mazzini <madsoenistata@gmail.com>

**Re: st: Loop year variable***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: Loop year variable***From:*emanuele mazzini <madsoenistata@gmail.com>

**Re: st: Loop year variable***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: Loop year variable***From:*emanuele mazzini <madsoenistata@gmail.com>

**Re: st: Loop year variable***From:*Nick Cox <njcoxstata@gmail.com>

**Re: st: Loop year variable***From:*emanuele mazzini <madsoenistata@gmail.com>

**Re: st: Loop year variable***From:*Nick Cox <njcoxstata@gmail.com>

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