You can produce a graph similar to the ggplot with lattice::barchart,

require(lattice)
dataset <- data.frame(Main=c("A","A","A","B","B"),
                      Detail=c("a","b","c","1","2"),
                      value=runif(5, min= 0.5, max=1))
barchart(value~Detail|Main, data=dataset,
         scales=list(x=list(relation="free")))

Walmes.

==========================================================================
Walmes Marques Zeviani
LEG (Laboratório de Estatística e Geoinformação, 25.450418 S, 49.231759 W)
Departamento de Estatística - Universidade Federal do Paraná
fone: (+55) 41 3361 3573
VoIP: (3361 3600) 1053 1173
e-mail: walmes@ufpr.br
twitter: @walmeszeviani
homepage: http://www.leg.ufpr.br/~walmes
linux user number: 531218
==========================================================================


On Wed, May 25, 2011 at 12:04 PM, Marc Schwartz <marc_schwartz@me.com>wrote:

> On May 25, 2011, at 7:56 AM, Victor Gabillon wrote:
>
> > Hello,
> >
> > I want to use the function barplot do display several group of bars.
> > A standard example is given at this link
> >
> http://onertipaday.blogspot.com/2007/05/make-many-barplot-into-one-plot.html
> >
> > But in their example the 4 groups of bars are all composed of 8 bars.
> > I want to be able do display the same kind of graph but where the number
> of bars in each group are not the same. For example the first group of bars
> would have 2 bars and the second group of bars would have 10 bars.
> >
> > barplot function has a first parameter named height which is a matrix
> where each line  are the values  for the bars of one particular group.
> > One solution could be to have a height matrix with NA values but then the
> space occupied by each group is equal to the size of the largest group!! So
> you end up with gaps (empty) where there are NAs.
> >
> > Do you know how to solve this problem?
> > Do i have to consider multiple barplots in the same plot with the same
> axis? (btw, i don't know how to do that)
> >
> > In fact the bar would represent the performance of an algorithm.
> > A group of bars would be the performance of an algorithms with different
> parameters.
> > But when comparing different algorithms it is possible that we don't want
> to display the same number of parameters for each algorithm.
> >
> > Thanks for your help.
> > Victor
>
>
> barplot() is fundamentally built upon the use of rect() to construct the
> bars, so you could always create your own variant to allow for the
> flexibility that you desire.
>
> That being said, if your performance measures (the bar heights) are other
> than discrete counts or proportions, I would advise you to consider using
> other visual presentation forms, as these are really the only two types of
> data for which barplots are generally considered satisfactory. A key to
> barplots of course is that they are based at 0 for proper visual comparison.
> Thus, if you need to have the minima of the relevant axis at a value other
> than 0, this is another reason to not use them.
>
> Even then, many folks have moved away from barplots to use point or dot
> plots and similar formats, especially where you also need to include some
> type of confidence interval for each measure.
>
> HTH,
>
> Marc Schwartz
>
> ______________________________________________
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>

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