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st: RE: Specification for a 1/0 variable with consecutive non-missing observations


From   "David Harrison" <david.harrison@icnarc.org>
To   <statalist@hsphsun2.harvard.edu>
Subject   st: RE: Specification for a 1/0 variable with consecutive non-missing observations
Date   Fri, 10 Jun 2005 16:39:01 +0100

Assuming your 40 variables are consecutively numbered in some way (here I have assumed var1-var40), the following (untested) code should be about right...

gen cons=0
gen maxcons=0
forvalues i=1/40 {
	replace cons=cons+1 if !missing(var`i')
	replace cons=0 if missing(var`i')
	replace maxcons=cons if cons>maxcons
}
gen byte cons20=maxcons>=20

The final variable (cons20) is the 1/0 variable you are after (maxcons will contain the longest run of consecutive non-missing variables).

Hope this helps

David

-----Original Message-----
From: Alejandro Delafuente
[mailto:alejandro.delafuente@st-antonys.oxford.ac.uk]
Sent: 10 June 2005 16:23
To: statalist@hsphsun2.harvard.edu
Subject: st: Specification for a 1/0 variable with consecutive
non-missing observations


Hi statalisters,
I have a time series for 40 years (40 continuos variables) and am trying to 
create a 1/0 variable that indicates 1 (for each row) if at least 20 variables 
in the series have consecutive non-missing values and 0 if this condition is 
not accomplished. I do have more than 20 non-missing values for most of the 
variables per row, but there are gaps (ie, missing values) between them. Thus I 
want to know how many fulfill the condition of 20 non-missing values in a road. 
Any clues as to how can I accomplish this with programming? 
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