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Re: st: Need help converting values into factor variable


From   Nick Cox <njcoxstata@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Need help converting values into factor variable
Date   Sat, 1 Dec 2012 12:17:26 +0000

This is not "Statlist"!

You should show us your code that you tried to get an explanation of
what you are getting wrong.

bysort patient (year) : gen flag = sum(year != year[_n-1] &
inrange(year, 2009, 2012))
by patient : replace flag = flag[_N]

Nick

On Sat, Dec 1, 2012 at 11:55 AM, Michael Stewart
<michaelstewartresearch@gmail.com> wrote:

> Dear Statlist reader ,
> I am having trouble converting  my values into factor variables and am
> looking for help. My data looks as follows where "patientid" is pt
> identification number and "year_elevated" is year in which a
> particular lab value was elevated
>
>
> patientid       year_elevated
> 111             2009
> 111             2009
> 222             2009
> 222             2011
> 222             2012
> 333             2009
> 333             2012
> 444             2011
> 444             2012
> 555             2009
> 555             2010
> 555             2011
> 555             2012
>
> I want to create a factor variable (y  )with values 1= ,2 , 3 and 4
> where  for each distinct patientid
> y=1 if year_elevated  has anyone of ( 2009 or 2010 or 2011 or 2012)  values
> y=2 if year_elevated  has  any two of ( 2009 , 2010 , 2011 ,  2012)  values
> y=3 if year_elevated has  any three of ( 2009 , 2010 , 2011 ,  2012)  values
> y=4 if year_elevated  has  all four of ( 2009 , 2010 , 2011 ,  2012) values
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