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Re: st: AW: alternative to forvalues combined with bysort, by


From   Kaspar Dardas <kaspar.dardas@students.ebs.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: AW: alternative to forvalues combined with bysort, by
Date   Mon, 28 Jun 2010 14:43:22 +0200

Hey Martin,


 -egen, tag()- takes a -varlist-, as far as I can see from its help
file, but does Stata allow you to add the "& inrange()..." part w/o
error?

Yep, absolutely. I get exactly what I need with this code but
unfortunately only for the entire datatset.  I have taken the code
from:

http://www.stata.com/statalist/archive/2008-08/msg00107.html

Maybe bysort does not work because of this. However, for one single
dataset it works absolutely fine.
Do you think  (egen, tag()- takes a -varlist-, as far as I can see
from its help file, but does Stata allow you to add the "&
inrange()...") is the problem, after all?

Thanks Martin and best,


Kaspar

2010/6/28 Martin Weiss <martin.weiss1@gmx.de>:
>
> <>
>
>
> " By the way, your
> solution "(forv i=1/`=_N'{" gets the exact same results as "quietly
> forvalues i = 1/`N' {""
>
>
>
> Again sorry, you defined a -local- up there which contained _N. But still, my line does it all in one, while you need two.
>
>
>
> " The easiest way would be to drop the remaining seven countries and do
> all this eight times. However, I would like to find a better solution.
> Maybe you have one last advice on this for me. Thanks for all of your
> help again!"
>
>
> This is not the easiest way, and I do not know of a single problem that requires you to -drop- outright. As I said earlier, the solution to this kind of problem is -bysort-, as described by NJC in http://www.stata-journal.com/sjpdf.html?articlenum=pr0004. Looping over all rows of the data, as in
>
> -forv i=1/`=_N'-
>
> is rarely necessary in Stata.
>
>
>
> " In each country 10000.
>
> --> egen tag = tag(transactionid) & inrange(eventdate, eventdate[`i']
> - 365, eventdate[`i'])"
>
>
> -egen, tag()- takes a -varlist-, as far as I can see from its help file, but does Stata allow you to add the "& inrange()..." part w/o error?
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Kaspar Dardas
> Gesendet: Montag, 28. Juni 2010 14:28
> An: statalist@hsphsun2.harvard.edu
> Betreff: Re: st: AW: alternative to forvalues combined with bysort, by
>
> Hi Martin,
>
> thanks for all the help and effort. You definitely do not have to be
> sorry. Its me who doesn't understand this stuff. Well, I am still
> struggling with it. I think, however, I know where the problem is but
> my Stata knowledge is just too bad to solve it. By the way, your
> solution "(forv i=1/`=_N'{" gets the exact same results as "quietly
> forvalues i = 1/`N' {"
>
> My actual problem is that I want to tag all "transactionsids" in ONE
> country 365 days prior to the current transaction. There are about
> 80000 transactions. In each country 10000.
>
> --> egen tag = tag(transactionid) & inrange(eventdate, eventdate[`i']
> - 365, eventdate[`i'])
>
> All of this works fine for one country (whenever I drop the other 7
> countries). However, whenever I try to use double loop version I still
> get the results for my entire datasample. Thus, (very simply speaking)
> all eight countries are treated as one. I think this has something do
> with
>
> local N = _N
> qui forval i = 1/`N' { (or your version forv i=1/`=_N)
>
> the _N refers to the entire dataset but I need somehow to apply the _N
> for each country separately so not for 80000 but rather for 8*10000
> observations. Stata also does not allow to use
>
> bysort location: local N = _N
>
> The easiest way would be to drop the remaining seven countries and do
> all this eight times. However, I would like to find a better solution.
> Maybe you have one last advice on this for me. Thanks for all of your
> help again!
>
>
> Best,
>
> Kaspar
>
> 2010/6/28 Martin Weiss <martin.weiss1@gmx.de>:
>>
>> <>
>>
>> Re your assertion that -bysort- and -forvalues- do not work together: This has never been a problem for me, since -bysort- is so incredibly useful and versatile. For an intro, see NJC`s http://www.stata-journal.com/sjpdf.html?articlenum=pr0004
>>
>>
>>
>> HTH
>> Martin
>>
>>
>> -----Ursprüngliche Nachricht-----
>> Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Martin Weiss
>> Gesendet: Montag, 28. Juni 2010 13:19
>> An: statalist@hsphsun2.harvard.edu
>> Betreff: AW: st: AW: alternative to forvalues combined with bysort, by
>>
>>
>> <>
>>
>> Sorry about my mistake, I never noticed you had a loop nested in there, b/c of the -quietly- command in front of it. One of the problems in your code is
>>
>> *************
>> quietly forvalues i = 1/`N' {
>> *************
>>
>> which should be - forv i=1/`=_N'{-
>>
>>
>> HTH
>> Martin
>>
>> -----Ursprüngliche Nachricht-----
>> Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Kaspar Dardas
>> Gesendet: Montag, 28. Juni 2010 12:30
>> An: statalist@hsphsun2.harvard.edu
>> Betreff: Re: st: AW: alternative to forvalues combined with bysort, by
>>
>> Martin,
>>
>> thanks for the prompt reply. Nesting two forvalues loops in a similar
>> fashion as my second solution which includes "foreach" ? I think you
>> are referring to something that I have already tried and showed in my
>> firs email, correct? Or did you mean something else? I think my first
>> email might have been not very precise. Again, my first command in the
>> below email should run over 8 countries. My second command is my
>> (failed) approach to solve it (which I think is similar to nesting two
>> forvalues loops)
>>
>> Best,
>>
>> Kaspar
>>
>> 2010/6/28 Martin Weiss <martin.weiss1@gmx.de>:
>>>
>>> <>
>>>
>>>
>>> You may want to nest two -forvalues- loops...
>>>
>>>
>>>
>>> HTH
>>> Martin
>>>
>>>
>>> -----Ursprüngliche Nachricht-----
>>> Von: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Kaspar Dardas
>>> Gesendet: Montag, 28. Juni 2010 12:11
>>> An: statalist@hsphsun2.harvard.edu
>>> Betreff: st: alternative to forvalues combined with bysort, by
>>>
>>> Hello,
>>>
>>> I would like to run the below forvalues loop for several countries
>>> ("locations") in one large dataset. Thus, I simply need to repeat this
>>> loop for subsets in one large dataset in the same fashion as the
>>> bysort: command would provide. "bysort:" , however, cannot be combined
>>> with forvalues.
>>>
>>> local N = _N
>>> gen count = .
>>> qui forval i = 1/`N' {
>>> egen tag = tag(transactionid) if gvkey == gvkey[`i'] &
>>> inrange(eventdate, eventdate[`i'] - 365, eventdate[`i'])
>>> count if tag
>>> replace count = r(N) in `i'
>>> drop tag
>>>  }
>>>
>>> Therefore, I have tried a foreach loop:
>>>
>>> foreach x in location {
>>>        gen count_all_trades = . if location == `x'
>>>        quietly forvalues i = 1/`N' {
>>>                egen tag = tag(transactionid) if location == `x' &
>>> inrange(eventdate, eventdate[`i'] - 365, eventdate[`i'])
>>>                count if tag & location == `x'
>>>                replace count_all_trades = r(N) in `i' if location == `x'
>>>                drop tag
>>>                }
>>> }
>>>
>>> However, this does not give me the correct solution. Is there anything
>>> similar to the "bysort:" command which can be used in combination with
>>> the forvalues command?
>>> Again, I simply need to rerun the first command for 8 different
>>> countries in one large dataset. Alliteratively, I could also split my
>>> dataset into 8 subsamples and run the above code 8 times. However, I
>>> would like to find a more "elegant" way to solve this problem.
>>>
>>> Best regards,
>>>
>>> Kaspar
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>>
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>
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