Hi martin,
thanks very much
I managed to arrive at the solution, i made two modifications to the
code. I created a indicator variable and then dropped the observations
from outside the loop also i changed the condition statement.
egen grp=group(id year)
gen ind=.
set trace on
levelsof grp, local(m)
foreach d of local m {
summ year if grp==`d'
local a=`r(mean)'
local b=`a'+1
di `a' " " `b'
replace ind=1 if month>m(`a'm4) & month <= m(`b'm4) & grp==`d'
}
drop if ind~=1
and that gives me exactly what i want..
id year month var1 grp ind
1 1980 1980m4 7 1 1
1 1980 1980m5 14 1 1
1 1980 1980m6 3 1 1
1 1980 1980m7 16 1 1
1 1980 1980m8 18 1 1
1 1980 1980m9 4 1 1
1 1980 1980m10 2 1 1
1 1980 1980m11 0 1 1
1 1980 1980m12 13 1 1
1 1980 1981m1 20 1 1
1 1980 1981m2 11 1 1
1 1980 1981m3 13 1 1
1 1980 1981m4 21 1 1
1 1981 1981m4 21 2 1
1 1981 1981m5 12 2 1
1 1981 1981m6 25 2 1
1 1981 1981m7 7 2 1
1 1981 1981m8 4 2 1
1 1981 1981m9 16 2 1
1 1981 1981m10 4 2 1
1 1981 1981m11 19 2 1
1 1981 1981m12 16 2 1
1 1981 1982m1 17 2 1
1 1981 1982m2 3 2 1
1 1981 1982m3 17 2 1
1 1981 1982m4 17 2 1
2 1980 1980m4 12 3 1
2 1980 1980m5 1 3 1
2 1980 1980m6 8 3 1
2 1980 1980m7 13 3 1
2 1980 1980m8 2 3 1
2 1980 1980m9 8 3 1
2 1980 1980m10 17 3 1
2 1980 1980m11 14 3 1
2 1980 1980m12 35 3 1
2 1980 1981m1 7 3 1
2 1980 1981m2 4 3 1
2 1980 1981m3 21 3 1
2 1980 1981m4 11 3 1
2 1981 1981m4 11 4 1
2 1981 1981m5 1 4 1
2 1981 1981m6 17 4 1
2 1981 1981m7 22 4 1
2 1981 1981m8 8 4 1
2 1981 1981m9 31 4 1
2 1981 1981m10 16 4 1
2 1981 1981m11 20 4 1
2 1981 1981m12 4 4 1
2 1981 1982m1 13 4 1
2 1981 1982m2 9 4 1
2 1981 1982m3 15 4 1
2 1981 1982m4 24 4 1
thanks very much for your time
regards
rich
2009/1/13 Martin Weiss <[email protected]>:
> Line for the server...
>
> Are you positively sure the evaluation order is correct in your -drop-
> statement (see [U]13.3)? Use braces where necessary! Note the different
> number of dropped observations in
>
> **********
> sysuse auto, clear
> drop if rep78==4 | f==1 & weight>2500
> sysuse auto, clear
> drop if (rep78==4 | f==1) & weight>2500
> **********
>
> HTH
> Martin
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of Richard Harvey
> Sent: Tuesday, January 13, 2009 12:42 PM
> To: [email protected]
> Subject: Re: st: RE: loops question
>
> hi,
>
> True.. Give that i am forming groups by id and year, that loop is not
> required. I could just say grp=group(id year).
>
> But once the grp had been defined and i run the following code..
>
> levelsof grp, local(m)
> foreach d of local m {
> summ year if grp==`d'
> local a=`r(mean)'
> local b=`a'+1
> di `a' " " `b'
> drop if month<m(`a'm4) | month>m(`b'm4) & grp==`d'
> }
>
> the drop if month<m(`a'm4) | month>m(`b'm4) & grp==`d' should be run
> for each grp seperately should it not?
>
> thanks
> rich
>
>
>
> 2009/1/13 Martin Weiss <[email protected]>:
>> Line for the server...
>>
>> This is much clearer and the story is complete now. It does not sound like
> a
>> standard task to me. I can spot a problem in
>>
>> sort id year month
>> levelsof id,local(l)
>> foreach c of local l {
>> egen grp=group(id year)
>> }
>>
>> You have at least two levels of id so the -foreach- would cycle at least
>> twice, but after the first run you already have a variable "grp". So the
>> second run through the loop should end with "grp already defined r(110)"?
>> Can you confirm that?(If you do not condition on c in the loop, what is
> the
>> loop good for anyway?)
>>
>> HTH
>> Martin
>>
>>
>> -----Original Message-----
>> From: [email protected]
>> [mailto:[email protected]] On Behalf Of Richard Harvey
>> Sent: Tuesday, January 13, 2009 12:06 PM
>> To: [email protected]
>> Subject: Re: st: RE: loops question
>>
>> hi martin,
>>
>> I am not sure what you mean by this " So far, as far as I can tell,
>> you have only told the list half the story..."
>>
>> I am sorry if i was not clear earlier. I will try to rephrase it
>>
>> The following is what i have
>> ***************************
>> id year month var1
>>
>> 1 1980 1980m1 x
>> 1 1980 1980m2 x
>> .......................
>> 1 1980 2006m12 x
>>
>> 1 1981 1980m1 x
>> 1 1981 1980m1 x
>> ........................
>> 1 1981 2006m12 x
>>
>> 2 1980 1980m1 x
>> 2 1980 1980m2 x
>> .......................
>> 2 1980 2006m12 x
>>
>> 2 1981 1980m1 x
>> 2 1981 1980m1 x
>> ........................
>> 2 1981 2006m12 x
>>
>>
>> The following is what i want
>> **********************
>> id year month var1
>>
>> 1 1980 1980m4 x
>> .......................
>> 1 1980 1981m4 x
>>
>> 1 1981 1981m4 x
>> 1 1981 1980m1 x
>> ........................
>> 1 1981 2006m12 x
>>
>> 2 1980 1980m1 x
>> 2 1980 1980m2 x
>> .......................
>> 2 1980 2006m12 x
>>
>> 2 1981 1980m1 x
>> 2 1981 1980m1 x
>> ........................
>> 2 1981 2006m12 x
>>
>> and the following is my code that attempts to achieve the above..
>>
>> ********start code**********
>>
>> * create grp as combination of id and year
>>
>> sort id year month
>> levelsof id,local(l)
>> foreach c of local l {
>> egen grp=group(id year)
>> }
>>
>> * loop over the groups to keep the relevant months
>>
>> levelsof grp, local(m)
>> foreach d of local m {
>> summ year if grp==`d'
>> local a=`r(mean)'
>> local b=`a'+1
>> di `a' " " `b'
>> drop if month<m(`a'm4) | month>m(`b'm4) & grp==`d'
>> }
>>
>> *******end code************
>>
>> and that gives me the following result
>>
>> id year month grp
>> 1181 1980 1981m4 1
>> 1181 1981 1981m4 2
>> 1181 1981 1981m5 2
>> 1181 1981 1981m6 2
>> 1181 1981 1981m7 2
>> 1181 1981 1981m8 2
>> 1181 1981 1981m9 2
>> 1181 1981 1981m10 2
>> 1181 1981 1981m11 2
>> 1181 1981 1981m12 2
>> 1181 1981 1982m1 2
>> 1181 1981 1982m2 2
>> 1181 1981 1982m3 2
>> 1181 1981 1982m4 2
>>
>> So it works fine for the second group but not for the first group.
>>
>> I am wondering why? I hope this is much better.
>>
>>
>> rich
>>
>> p.s what does Line for the server... mean???
>>
>>
>> 2009/1/13 Martin Weiss <[email protected]>:
>>> Line for the server...
>>>
>>> " What am I doing wrong?"
>>>
>>> The answer to that depends on how the outcome of your proposed solution
>>> differs from what you want to achieve.
>>>
>>> HTH
>>> Martin
>>>
>>>
>>> -----Original Message-----
>>> From: [email protected]
>>> [mailto:[email protected]] On Behalf Of Richard Harvey
>>> Sent: Tuesday, January 13, 2009 11:33 AM
>>> To: [email protected]
>>> Subject: st: loops question
>>>
>>> Hi all,
>>>
>>> I have a dataset set up as follows
>>>
>>> id year month var1
>>>
>>> 1 1980 1980m1 x
>>> 1 1980 1980m2 x
>>> .......................
>>> 1 1980 2006m12 x
>>>
>>> 1 1981 1980m1 x
>>> 1 1981 1980m1 x
>>> ........................
>>> 1 1981 2006m12 x
>>>
>>> 2 1980 1980m1 x
>>> 2 1980 1980m2 x
>>> .......................
>>> 2 1980 2006m12 x
>>>
>>> 2 1981 1980m1 x
>>> 2 1981 1980m1 x
>>> ........................
>>> 2 1981 2006m12 x
>>>
>>> for each id year combination i want to keep the months from april of
>>> that year to april of next year.
>>>
>>> i.e for id 1 and year 1980 combination i want to keep months from
>>> april 1980 to april 1981.
>>> again for id 1 and year 1981 combination i want to keep months from
>>> april 1981 to april 1982.
>>>
>>> then for,
>>>
>>> id 2 and year 1980 combination i want to keep months from april 1980
>>> to april 1981.
>>> again for id 2 and year 1981 combination i want to keep months from
>>> april 1981 to april 1982
>>>
>>> so the finaldataset should look like
>>>
>>> id year month var1
>>>
>>> 1 1980 1980m4 x
>>> .......................
>>> 1 1980 1981m4 x
>>>
>>> 1 1981 1981m4 x
>>> 1 1981 1980m1 x
>>> ........................
>>> 1 1981 2006m12 x
>>>
>>> 2 1980 1980m1 x
>>> 2 1980 1980m2 x
>>> .......................
>>> 2 1980 2006m12 x
>>>
>>> 2 1981 1980m1 x
>>> 2 1981 1980m1 x
>>> ........................
>>> 2 1981 2006m12 x
>>>
>>>
>>> My logic was first to create a variable grp, where grp=group(id
>>> year), then loop over the grps to keep the relevant months. What am i
>>> doing wrong?
>>>
>>> ********start code**********
>>>
>>> * create grp as combination of id and year
>>>
>>> sort id year month
>>> levelsof id,local(l)
>>> foreach c of local l {
>>> egen grp=group(id year)
>>> }
>>>
>>> * loop over the groups to keep the relevant months
>>>
>>> levelsof grp, local(m)
>>> foreach d of local m {
>>> summ year if grp==`d'
>>> local a=`r(mean)'
>>> local b=`a'+1
>>> di `a' " " `b'
>>> drop if month<m(`a'm4) | month>m(`b'm4) & grp==`d'
>>> }
>>>
>>> *******end code************
>>>
>>> --
>>> thanks for your time
>>> rich
>>> *
>>> * For searches and help try:
>>> * http://www.stata.com/help.cgi?search
>>> * http://www.stata.com/support/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/statalist/faq
>>> * http://www.ats.ucla.edu/stat/stata/
>>>
>>
>>
>>
>> --
>> thanks for your time
>> rich
>> *
>> * For searches and help try:
>> * http://www.stata.com/help.cgi?search
>> * http://www.stata.com/support/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/statalist/faq
>> * http://www.ats.ucla.edu/stat/stata/
>>
>
>
>
> --
> thanks for your time
> rich
> *
> * For searches and help try:
> * http://www.stata.com/help.cgi?search
> * http://www.stata.com/support/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/statalist/faq
> * http://www.ats.ucla.edu/stat/stata/
>
--
thanks for your time
rich
*
* For searches and help try:
* http://www.stata.com/help.cgi?search
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
