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Re: st: Summarizing data by Timestamps


From   Diego Bellavia <messadua@yahoo.it>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Summarizing data by Timestamps
Date   Mon, 7 Dec 2009 19:44:38 +0000 (GMT)

Great !!

It sounds perfect to me, I will give it a try and let you know. 
Thanks a bunch : )

Diego

--- Lun 7/12/09, Eric Booth <ebooth@ppri.tamu.edu> ha scritto:

> Da: Eric Booth <ebooth@ppri.tamu.edu>
> Oggetto: Re: st: Summarizing data by Timestamps
> A: statalist@hsphsun2.harvard.edu
> Data: Lunedì 7 dicembre 2009, 20:19
> ><
> >
> 
> Diego:
> 
> I added some extra timestamps since you were interested in
> time periods of a couple of hours:
> 
> 
> ****
> clear
> 
> input str20 timestamp         
> pressure 
> "11/22/09 00:00"        120
> "11/22/09 00:01"        123
> "11/22/09 00:02"        119
> "11/22/09 00:03"        115
> "11/22/09 00:09"        123
> "11/22/09 00:10"        122
> "11/22/09 00:22"        112
> "11/22/09 01:20"        2000
> "11/22/09 01:27"        2100
> "11/22/09 05:27"        
> 5000
> "11/22/09 06:45"       
> 10000
> end
> 
> *format timestamp %tCNNDDYY_HH:MM
> g double timestamp2 = clock(timestamp, "MD20Yhm")
> 
> **avg. by one hour interval**
> g hour = hh(timestamp2)
> egen one_hour_avg = mean(pressure), by(hour)
> 
> **take averages for different time periods from 1:00**
> forv t = 2(1)6 {
> egen hour_avg_`t' = mean(pressure)if hour<=(1+`t') &
> hour>=1
> }
> 
> **or by collapse to get summary info by hour, etc**
> preserve
> collapse (mean) pressure , by(hour)
> li
> restore
> *****
> 
> 
> ~Eric
> __
> Eric A. Booth
> Public Policy Research Institute
> Texas A&M University
> ebooth@ppri.tamu.edu
> Office: +979.845.6754
> 
> 
> 
> On Dec 7, 2009, at 12:51 PM, Diego Bellavia wrote:
> 
> > Hello StataListers, 
> > 
> > I have such a dataset: 
> > 
> > Timestamp       
>    Pressure 
> > 11/22/09 00:00        120
> > 11/22/09 00:01        123
> > 11/22/09 00:02        119
> > 11/22/09 00:03        115
> > 11/22/09 00:09        123
> > 11/22/09 00:10        122
> > 11/22/09 00:22        112
> > 
> > etc...
> > 
> > As you see, Pressure values are reported by time
> (defined as a timestamp) every minute.
> > Unfortunately, the system is not so precise to collect
> pressure every single minute so, 
> > I do not necessarily have 60 measures in 1 hour. 
> > Now I would like to compute averages for Pressure
> every pre-spcified time range, starting, as exmaple, 
> > with ana average of all the values collected between
> 00:00 and 01:00 on 11/22/2009 but also being able to 
> > change the time range from 1 hour, to 4 or 6 hours and
> so on. 
> > 
> > How can I do that in STATA, considering that I do not
> know how many measure are collected per hour ? 
> > 
> > Thank you in advance, 
> > 
> > Diego
> > 
> > 
> > 
> > 
> 
> 
> 
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