Notice: On March 31, it was **announced** that Statalist is moving from an email list to a **forum**. The old list will shut down on April 23, and its replacement, **statalist.org** is already up and running.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

From |
Nick Cox <njcoxstata@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Loop year variable |

Date |
Mon, 22 Oct 2012 10:23:38 +0100 |

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/

**Follow-Ups**:**Re: st: Loop year variable***From:*emanuele mazzini <madsoenistata@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>

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

- Prev by Date:
**Re: st: oligit interpretation** - Next by Date:
**RE: st: How to insert scalars (elements from Stata's matricies) as locals' values in the 'forvalues' command?** - Previous by thread:
**Re: st: Loop year variable** - Next by thread:
**Re: st: Loop year variable** - Index(es):