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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 11:05:28 +0200 |

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/

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

**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>

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