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Re: st: Re: Request code simplification


From   Michael Stewart <michaelstewartresearch@gmail.com>
To   statalist <statalist@hsphsun2.harvard.edu>
Subject   Re: st: Re: Request code simplification
Date   Wed, 12 Jun 2013 12:58:23 -0400

No problem rebecca.
Thanks
Mike

On Wed, Jun 12, 2013 at 11:58 AM, Rebecca Pope <rebecca.a.pope@gmail.com> wrote:
> Sorry, just saw the correction & answers posted by others.
> http://www.stata.com/statalist/archive/2013-06/msg00499.html
>
> -Rebecca
>
> On Wed, Jun 12, 2013 at 9:26 AM, Rebecca Pope <rebecca.a.pope@gmail.com> wrote:
>> Mike,
>> First things first, a point of order: -carryforward- is a user-written
>> command and you are asked to please identify these when you use them
>> and note from where you have obtained them.
>>
>> Second, I tested your (slightly modified) code on my computer using a
>> test set built off of what you posted with a total of 270,000
>> observations (you just said "thousands", so I made it of moderate
>> size). Total run time was 0.79 seconds. So, if you are having computer
>> problems, my suggestion would be to check what else is running on your
>> computer.
>>
>> Finally, this may be a stupid question, but if you are trying to find
>> patients with transplants, why aren't you searching for type_of_visit
>> = (code for transplant). Does the other stuff you posted serve some
>> greater purpose you didn't mention?
>>
>> There are multiple ways of handling the code for searching for
>> transplants. The easiest, I think, would simply be:
>>
>> *** begin example ***
>> gen transplant = -1*strmatch(type_of_visit,"*transplant")
>> bys pat_id (transplant): gen countthis = (-1*transplant) if _n==1
>>
>> tab countthis
>> *** end example ***
>>
>> The code above ran in 0.22 seconds. Timing is from a machine with 4 GB
>> of RAM and an Intel Core i5-2400 3.1 GHz processor. Performance on
>> your laptop will likely differ, but I see no reason why either
>> approach would cause a crash.
>>
>> Regards,
>> Rebecca
>>
>> On Tue, Jun 11, 2013 at 4:14 PM, Michael Stewart
>> <michaelstewartresearch@gmail.com> wrote:
>>> Hello,
>>>
>>> I am  working on a data set with thousands of patients( and multiple
>>> records per patient) and I am trying to identify pateints with any
>>> transplant(could undergo liver, kidney, intestine etc) . I was
>>> wondering if we could simplify my  code as my laptop is freezing with
>>> the following set of commands.
>>>
>>>
>>> Here the goal is find patients who has
>>> type_of_visit[1]=="first_clinic_visit" & any other type_of_visit is
>>> "".(after the records are sorted by pat_id and visit_date)
>>>
>>> My code :
>>>
>>> bysort PAT_ID (visit_date):carryforward VISIT,gen(v)
>>> bysort PAT_ID (visit_date):gen x=v[1]==v[_n]
>>> bysort PAT_ID (visit_date):egen z=sum(x)
>>> bysort PAT_ID (visit_date):egen zz=count(x)
>>> gen y= z< zz
>>>
>>>
>>> The dataset format is as follows.
>>>
>>> pat-id     visit_date     type_of_visit
>>> -------------------------------------------------------
>>> xxx      09/01/2003      first_clinic_visit
>>> xxx      09/15/2003
>>>                 .
>>>                 .
>>>                 .
>>>                 .
>>> XXX      12/12/2003
>>> XXX      2/04/2004       liver_transplant
>>> yyy      01/01/2004      first_clinic_visit
>>> yyy      02/02/2005
>>>                  .
>>>                   .
>>> yyy     01/03/2008      intestine_transplant
>>> zzz      05/01/2010     first_clinic_visit
>>> zzz     05/03/2011
>>>                   .
>>>                   .
>>>                   .
>>>                   .
>>> ------------------------------------------------------------
>>>
>>> As always, thanks a lot for your time
>>> Thank you ,
>>> Yours Sincerely,
>>> Mike.
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-- 
Thank you ,
Yours Sincerely,
Mike.
*
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