Try this: boxplot(as.matrix(data) ~ as.Date(date), cex.axis = 0.5, las = 2)
or if all the dates are in the same year and month as they are here then you might want to just display the day of the month: boxplot(as.matrix(data) ~ month.day.year(date)$day) On Sun, May 31, 2009 at 1:45 PM, Kenneth Takagi <kat...@psu.edu> wrote: > Hi, > > > > I'm having trouble using dates (created using library(chron)) as > groupings for a boxplot. I have 10 repeat measurements of a variable > within an individual day. The measurements were done over 10 days. I > would like to plot the measurements as a box and wisker plot (using > boxplot or something similar) where the days (as chron object) would be > the grouping and the repeated measurements of the variable make up the > box and wisker plot. I would like the spacing of the individual > boxplots to reflect the time between measurements: > > > > Example using random numbers: > > > > ### Create date vector of measurement dates > > library(chron) > > time=c(39083, 39085, 39095, 39096, 39103, 39104, 39105, 39110, 39113, > 39120); > > orig =chron("01/01/1900") > > date = orig + time-2; > > > > ### Data for B and W plot > > data = data.frame(); > > mean=rnorm(10, mean=0, sd=1); > > for(i in 1:10){data[1:10,i] =rnorm(10, mean=mean[i], sd=1)}; > > > > ### Plot > > boxplot(data, range=0); # works, but doesn't reflect the different time > intervals between measurements dates! > > boxplot(data~date, range=0) # tried using formula, gives error: > > Error in model.frame.default(formula = data ~ date) : > > invalid type (list) for variable 'data' > > > > Not sure what to try next. Any suggestions? > > > > Thanks, > > ken > > > > kat...@psu.edu > > > > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > 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. > ______________________________________________ R-help@r-project.org mailing list 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.