><
>
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
[email protected]
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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