Does table(DF$Time) do what you want? Seems kinda odd to me that you want to distinguish between 18:31 and 18:32 but you don't care which days those occur on. If your phenomenon is related to local time-of-day then perhaps you might want to correlate with sun elevation relative to the horizon. If you have lat/lon and timezone then the maptools package can estimate local sun position from datetime.
On November 30, 2020 7:48:00 AM PST, Neotropical bat risk assessments and acoustic tools <[email protected]> wrote: >Hi all, > >I need to summarize temporal activity. However date\times in R seem to >be not easily handled. >Seems I may need to convert date\time values to a recognizable format? > >My "raw data" is tab (text) includes a location ID, date and time(24 hr > >format). >Format is like this: >Location Date Time >156 2/25/2008 18:31 >156 2/25/2008 18:31 >156 2/25/2008 18:32 >156 2/25/2008 18:35 >156 2/25/2008 18:38 >156 2/25/2008 18:41 >156 2/25/2008 18:42 >156 2/25/2008 18:43 >156 2/25/2008 18:43 >156 2/25/2008 18:55 >156 2/25/2008 18:56 >156 2/25/2008 18:56 >156 2/26/2008 18:35 >156 2/26/2008 18:35 >156 2/26/2008 18:35 >156 2/26/2008 18:35 >196 7/16/2006 4:47 >250 4/9/2004 18:41 >250 4/9/2004 18:44 >253 3/5/2004 18:30 >1268 2/11/2001 18:39 >1268 2/11/2001 18:39 >1344 4/17/2003 19:06 >1409 2/28/2004 5:51 >...etc. for 10,390 rows of data. > >I am aiming for a summary by times for all of the data such that I have > >total number of "events" or count for each time period. So something >like > >18:31 41 >18:32 38 > >and so on. > >So a "simple" count of the time occurrences. > >I tried to do a summary running frequencies >descriptive.table(vars = d(Time) , >+ strata = d(Date),data= Active, >+ func.names =c("Valid N","Minimum","Maximum")) > > >Warning message: >In descriptive.table(vars = d(Time), strata = d(Date), data = Active, >: > Non-numeric variables dropped from descriptive table > > Active[,3]<-as.POSIXct(Active[,3], format='%m-%d-%y %H:%M:%S') > > Active[,2]<-as.Date(Active[,2], format= '%m/%d/%y') > > frequencies(Active[c("Time")] , r.digits = 1) >Error in names(x) <- value : > 'names' attribute [4] must be the same length as the vector [3] > >Suggestions welcomed. > >Cheers all -- Sent from my phone. Please excuse my brevity. ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
