I'd like to make a plot showing frequency of an event. The data
is in a data from that includes Year, Month and Day (of month)
fields, so I created a Date with ISOdate(Year, Month, Day,
tz=''). I can plot frequencies for the year 2002 with
> thisyear <- Date[Year==2002]
> hist( thisyear, xaxt='n' )
> axis.POSIXct( 1, at=seq(min(thisyear), max(thisyear),
by="month"),
format='%b %Y' )
Now I want to specify the histogram breaks so that there is one
bin per month, so I tried this:
> hist( thisyear,
breaks=ISOdate( rep(2002,12), seq(12), rep(1,12), tz='' ),
xaxt='n' )
That resulted in an error message that said:
Error in Ops.POSIXt(1e-07, mean(h)) : * not defined for POSIXt objects
Can anyone suggest a way to do this? Or another method for
plotting this sort of month by month frequency plot? For a
single year I could histogram the month, but I'd like to be able
to span any date range, including multiple years.
Mike
--
Michael A. Miller mmiller3 at iupui.edu
Imaging Sciences, Department of Radiology, IU School of Medicine
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One way would be to convert to POSIXlt and extract the month element. Then you should be able to tabulate the number of events in each month, and make a barplot of those. -Don At 4:57 PM -0500 5/28/02, Michael A. Miller wrote:>I'd like to make a plot showing frequency of an event. The data >is in a data from that includes Year, Month and Day (of month) >fields, so I created a Date with ISOdate(Year, Month, Day, >tz=''). I can plot frequencies for the year 2002 with > > > thisyear <- Date[Year==2002] > > hist( thisyear, xaxt='n' ) > > axis.POSIXct( 1, at=seq(min(thisyear), max(thisyear), by="month"), > format='%b %Y' ) > >Now I want to specify the histogram breaks so that there is one >bin per month, so I tried this: > > > hist( thisyear, > breaks=ISOdate( rep(2002,12), seq(12), rep(1,12), tz='' ), > xaxt='n' ) > >That resulted in an error message that said: > > Error in Ops.POSIXt(1e-07, mean(h)) : * not defined for POSIXt objects > >Can anyone suggest a way to do this? Or another method for >plotting this sort of month by month frequency plot? For a >single year I could histogram the month, but I'd like to be able >to span any date range, including multiple years. > >Mike > >-- >Michael A. Miller mmiller3 at iupui.edu > Imaging Sciences, Department of Radiology, IU School of Medicine >-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- >r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html >Send "info", "help", or "[un]subscribe" >(in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch >_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Thanks for all the suggestions. After fiddling alonw the lines
of your suggestions, I found a solution in the examples in
hist.POSIXt:
hist(thisyear,
breaks=seq(ISOdate(2000,1,1),ISOdate(2003,1,1),by='month'))
hist(thisyear,
breaks=seq(ISOdate(2000,1,1),ISOdate(2003,1,1),by='week'))
Thanks!
Mike
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