st: Re: Average and count from a given number of previous observations

["Steven Proud" <steven_proud@hotmail.com>]

One way of doing this would be with a loop

so, could:
tsset date
local i=1
while `i'<=84 {
gen l`i'rainfall=l`i'.rainfall
local i=`i'+1
}
gen lag28rainfall=rsum(l1rainfall-l28rainfall)
gen lag84rainfall=rsum(l1rainfall-l84rainfall)
drop l1rainfall-l84rainfall


gen rain=0
replace rain=1 if rainfall>0
local i=1
while `i'<=84 {
gen l`i'rain=l`i'.rain
local i=`i'+1
}

gen lag28rain=rsum(l1rain-l28rain)
gen lag84rain=rsum(l1rain-l84rain)
drop l1rain-l84rain

I think that should work

**********************************************
----- Original Message ----- 
From: "Patrick Woodburn" <Patrick.Woodburn@mrcuganda.org>
To: <statalist@hsphsun2.harvard.edu>
Sent: Tuesday, December 11, 2007 8:01 AM
Subject: st: Average and count from a given number of previous observations



> Dear Statalist,
>
> I have weather data for a site in Uganda which I'm hope to compare to
> malaria data.  My rainfall data is a single variable, sorted by date,
> with no missing data, along the following lines:
>
> date           rainfall (ml)
> 01jan2003       12.7 
> 02jan2003        3.0
>
> ...
>
> 31jun2007        1.3
>
> I would like to make four new variables for each date.  Two to represent
> the total rainfall across the previous 28 days and across the previous
> 84 days, and two to represent the total number of days on which
> rainfall>0 out of the previous 28 or 84 days.   Could someone suggest
> how best to do this?
>
> Best regards,
>
> Patrick
>
>
>
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