gap.barplot doesn't support data arrays?

-----Original Message-----
From: Jim Lemon [mailto:jim at bitwrit.com.au]
Sent: Tuesday, April 05, 2011 2:12 PM
To: Andrew D. Steen
Cc: r-help at r-project.org
Subject: Re: [R] gap.barplot doesn't support data arrays?

On 04/04/2011 11:39 PM, Andrew D. Steen wrote:

I am trying to make a barplot with a broken axis using gap.barplot

(in

the indispensable plotrix package).

Aww, gee, you've won me.

This works well when the data is a vector:

twogrp<-c(rnorm(10)+4,rnorm(10)+20)

gap.barplot(twogrp,gap=c(8,16),xlab="Index",ytics=c(3,6,17,20),ylab="

Group

values",main="Barplot with gap")

But when the data is an array (for a bar plot with multiple series) I
get an error and a strange plot with no y-tics and bars stretching
downwards, as if all the values were negative:

twogrp2<-array(twogrp, dim=c(2,5))

gap.barplot(twogrp2,gap=c(8,16),xlab="Index",ytics=c(3,6,17,20),ylab="

Group
values",main="Barplot with gap")

Error in rect(xtics[bigones] - halfwidth, botgap, xtics[bigones] +
halfwidth,  :
   cannot mix zero-length and non-zero-length coordinates

However, the main title and axis labels do appear correctly.

Are data arrays unsupported for gap.barplot, or am I missing

something?

Hi Drew,
You are right, as is Peter, gap.barplot doesn't support arrays, only
vectors (I'll fix the docs). However, it wasn't too hard to whip up a
rough but perhaps serviceable fix in the attached function. You may
need to do some mods to the function to get exactly what you want. Try
this:

# your twogrp2 left out the high values
twogrp2<-array(twogrp,dim=c(2,10))
source("gap.barp.R")
gap.barp(twogrp2,gap=c(8,16),xlab="Index",ytics=c(3,6,17,20),
  xtics=1:10,ylab="Groupvalues",main="Barplot with gap",col=2:3)

gap.barp returns the modified y values so that you can include the
error bars.

To paraphrase the immortal P.J. O'Rourke,

"Perhaps R users shouldn't do some things in plots, but they certainly
can do them"

Jim