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st: RE: generating a variable that requires comparing two dates
From
"Ariel Linden, DrPH" <[email protected]>
To
<[email protected]>
Subject
st: RE: generating a variable that requires comparing two dates
Date
Thu, 11 Apr 2013 16:00:20 -0400
As a follow up to my earlier posting, there is a user-written command
-vlookup- (findit vlookup) that does exactly what I want, however it is not
"byable"
vlookup surveydate, gen(alrt_day) key(admitdate) value(alert)
Ariel
-----Original Message-----
From: Ariel Linden, DrPH [mailto:[email protected]]
Sent: Thursday, April 11, 2013 3:17 PM
To: [email protected]
Subject: generating a variable that requires comparing two dates
Hi fellow listers,
This may be an easy task, but I am not getting it right...
I would like to generate a new variable ( by ID) that will equal 1 if there
was an alert (triggered on the surveydate, when that surveydate was the same
as the admitdate. The obvious problem is that the dates are not always
aligned so a straight "bys ID: gen test if surveydate==admitdate & alert==1"
will not always work.
In the data below, the code would need to "see" that the admitdate of
4/6/2011 has a corresponding surveydate a few lines down where the alert==1.
Similarly, the next admitdate is 4/20/2011, so it would need to lookup the
corresponding surveydate and verify that alert==1.
I would then like to run this code again (generating a new variable) where
we'd look to see if there was an alert on the surveydate the day before the
admitdate (ie., surveydate = admitdate - 1)
Thanks in advance!
Ariel
**** example data****
ID surveydate alert admitdate
1 4/2/2011 1 4/6/2011
1 4/3/2011 1 4/20/2011
1 4/4/2011 0 4/20/2011
1 4/5/2011 0 4/20/2011
1 4/6/2011 1 4/20/2011
1 4/7/2011 0 4/20/2011
1 4/8/2011 0 4/20/2011
1 4/9/2011 0 4/20/2011
1 4/10/2011 0 4/20/2011
1 4/11/2011 0 4/20/2011
1 4/12/2011 0 4/20/2011
1 4/13/2011 0 4/20/2011
1 4/14/2011 0 4/20/2011
1 4/15/2011 0 4/20/2011
1 4/16/2011 0 4/20/2011
1 4/17/2011 0 4/20/2011
1 4/18/2011 0 4/20/2011
1 4/19/2011 0 4/20/2011
1 4/20/2011 1 4/20/2011
1 4/21/2011 0 4/20/2011
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