[R] Odp: preparing data for barplot()

[Petr PIKAL]

Hi

Read what barplot does and look to your plot.

If you want each row to be plotted as stacked bar with names uder each bar 
taken from peaople variable then you need to 

transpose your matrix - barplot takes columns
plot without names - you do not want them really plotted
add names under each bar - that is what names.arg is for

barplot(t(data.matrix(fakedata[,-1])), names.arg=fakedata$people)

Regards
Petr

r-help-bounces at r-project.org napsal dne 03.03.2009 19:00:12:

> What is the best way to produce a barplot from my data?  I would like
> the barplot to show each person with the values stacked
> val1+val2+val3, so there is one bar for each person  When I use
> barplot(data.matrix(realdata)), it shows one bar for each value
> instead.
> 
> To post here, I created an artificical data set, but it works fine.
> 
> fakedata <- as.data.frame(list(LETTERS[1:3]))
> colnames(fakedata) <- 'people'
> fakedata['val1'] = abs(rnorm(3))
> fakedata['val2'] = abs(rnorm(3))
> fakedata['val3'] = abs(rnorm(3))
> barplot(data.matrix(fakedata))
> 
> At a glance there is no substantial difference is between my fake data
> and my real data.
> 
> > realdata
>   person val1 val2 val3
> 1      A  221   71  175
> 2      B  222   85  147
> > mydata
>   people       val1     val2       val3
> 1      A 0.75526748 0.445386 0.09186245
> 2      B 0.06107566 2.008815 2.50269410
> 3      C 0.47171611 0.592037 0.57612168
> 
> However
> 
> > data.matrix(realdata)
>   person val1 val2 val3
> 1     NA  221   71  175
> 2     NA  222   85  147
> Warning messages:
> 1: NAs introduced by coercion
> 2: NAs introduced by coercion
> 
> So then I converted 'person' from a list to factors, which removed the
> coercision error, but barplot() still shows each bar as value instead
> of a person.
> 
> My serialized() data subset is here (look at bottom half where there
> are no line numbers)
> http://pastebin.com/m6d1e1d79
> 
> 
> Thanks in advance,
> Andrew
> 
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