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Re: st: aggregate by high frequency data


From   Maarten Buis <maartenlbuis@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: aggregate by high frequency data
Date   Wed, 27 Jun 2012 18:16:36 +0200

On Wed, Jun 27, 2012 at 5:39 PM, tashi lama wrote:
> If I want to aggregate hits per day, then I would do sth like
>
> gen daily=dofc(read_date)
>
> collapse (sum) hits, by(daily)
>
> Does anyone have any idea aggregating per min or per hr or per sec for that matter? There doesn't seem to have a date-related command to do that both in manual and help?

see -help datetime-, in particular the section labeled "Extracting
time-of-day components from SIFs"

*------------- begin example ------------------
clear
input str18 read_date  byte hits
"04jan2011 01:01:41"      1
"04jan2011 01:03:07"      1
"04jan2011 01:04:06"      1
"04jan2011 01:08:21"      1
"04jan2011 01:09:28"      1
"04jan2011 01:58:34"      1
"04jan2011 02:05:04"      1
"04jan2011 02:16:45"      1
"04jan2011 02:18:06"      1
"04jan2011 02:22:34"      1
end

gen double date = clock(read_date, "DMYhms")
format date %tc
gen float daily = dofc(date)
format daily %td
gen byte hourly = hh(date)

collapse (sum) hits, by(daily hourly)
list
*-------------- end example -------------------
(For more on examples I sent to the Statalist see:
http://www.maartenbuis.nl/example_faq )


-- Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------
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