[R] Boxplot with Log10 and base-exponent axis

[Martin Maechler]

> The key is to supply an expression, not text, to the labels argument to axis.
> See help("plotmath") for details.  Here is an example:


>   x <- list(One=10^(sin(1:10)+5), Two=10^(cos(1:30)*2))
>   boxplot(x, log="y", yaxt="n")
>   ylim <- par("usr")[3:4]
>   log10AtY <- seq(ceiling(ylim[1]), floor(ylim[2]))
>   axis(side=2, at=10^log10AtY, lab=as.expression(lapply(log10AtY, function(y)bquote(10^.(y)))))

Yes, that's nice, and exactly the basic idea.

For a few years now,  the  eaxis() function in package "sfsmisc" 
does (something like) this (and a bit more) even more nicely :

 install.packages("sfsmisc")
 require("sfsmisc")

 x <- list(One=10^(sin(1:10)+5), Two=10^(cos(1:30)*2))
 boxplot(x, log="y", yaxt="n")
 eaxis(2)

--
Martin Maechler, ETH Zurich

> Bill Dunlap
> Spotfire, TIBCO Software
> wdunlap tibco.com

> > -----Original Message-----
> > From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On Behalf
> > Of Luigi
> > Sent: Friday, June 22, 2012 7:54 AM
> > To: r-help at r-project.org
> > Subject: [R] Boxplot with Log10 and base-exponent axis
> > 
> > Dear all,
> > 
> > I would like to (i) produce boxplot graphs with axis in logarithm in base 10
> > and (ii) showing the values on the axis in 10^exponent format rather than
> > 10E+exponent.
> > 
> > 
> > 
> > To illustrate with an example, I have some widely spread data that I chart
> > plot using  boxplot() [figure on the left]; the log="y" option of boxplot()
> > I obtained the natural logarithm conversion of the data and the unfriendly
> > notation baseE+exponent [figure on the centre]; if I log10 the data I obtain
> > the desired plot, but the axis are showing only the exponent. [figure on the
> > right].
> > 
> > 
> > 
> > Can anybody help?
> > 
> > 
> > 
> > Best regards
> > 
> > Luigi Marongiu, MSc
> > 
> > 
> > 
> > ########### EXAMPLE ############
> > 
> > # generationg random numbers
> > 
> > x<-runif(100, min=0, max=100000)
> > 
> > 
> > 
> > # create plot
> > 
> > par(mfrow = c(1,3))
> > 
> > 
> > 
> > #plotting in the left side
> > 
> > boxplot(x, xlab="Linear values")
> > 
> > 
> > 
> > #plotting in the centre
> > 
> > boxplot(x, log = "y", xlab="y axis logged")
> > 
> > 
> > 
> > # creating log10 values and plotting on the right side
> > 
> > Log.base10.x<-log10(x)
> > 
> > boxplot(Log.base10.x, xlab="LOG10 of data")
> > 
> > 
> > 
> > 
> > 
> > 
> > 	[[alternative HTML version deleted]]
> > 
> > ______________________________________________
> > R-help at 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.