[R] help on barplot

Marc Schwartz MSchwartz at medanalytics.com
Mon Jul 21 06:34:50 CEST 2003

On Sun, 2003-07-20 at 21:16, Murad Nayal wrote:
> Hello,
> I am trying to compare two histograms using barplot. the idea is to plot
> the histograms as pairs of columns side by side for each x value. I was
> able to do it using barplot before but I can't remember now for the life
> of me now how I did it in the past:
> > d
>               [,1]         [,2]
> -37.5 0.0000000000 2.789396e-05
> -32.5 0.0001394700 5.578801e-05
> -27.5 0.0019804742 1.732218e-02
> -22.5 0.0217294282 1.380474e-01
> -17.5 0.0938912134 4.005579e-02
> -12.5 0.0630683403 4.351464e-03
> -7.5  0.0163179916 8.368201e-05
> -2.5  0.0025941423 5.578801e-05
> 2.5   0.0002789400 0.000000e+00
> 7.5   0.0000000000 0.000000e+00
> > barplot(d,beside=TRUE)
> barplot here plots two separate 'sets' of columns, on the left side a
> bar plot of d[,1] is plotted while on the right side a separate bar plot
> of d[,2] is plotted. how can I combine the two?
> actually, while on the subject of histograms. is it possible to plot a
> 3D-histogram in R (a true 3D bar plot, without using image).
> many thanks
> Murad

You need to restructure the data passed to barplot() so that the two
'height' related columns are converted to 2 rows of 10 columns. Each
column is then drawn as pairs of bars:

barplot(rbind(d[, 1], d[, 2]), beside = TRUE)

Take a look at the change in structure as a result of:

rbind(d[, 1], d[, 2])

In terms of 3d histograms, it would appear that Duncan Murdoch, Daniel
Adler et al are working on porting Duncan's Windows only DJMRGL package
(http://www.stats.uwo.ca/faculty/murdoch/software) to multiple platforms
at (http://wsopuppenkiste.wiso.uni-goettingen.de/~dadler/rgl). If my
read is correct, it looks like they have some of the primitives ready to
go at this time, but perhaps have not yet converted Duncan's hist3d()


Marc Schwartz

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