[R] Boxplot across levels of a factor

[Paul Boutros]

Thank you: works like a charm.
Paul

> -----Original Message-----
> From: Prof Brian Ripley [mailto:ripley at stats.ox.ac.uk]
> Sent: Tuesday, August 24, 2004 2:28 AM
> To: Paul Boutros
> Cc: R-Help
> Subject: Re: [R] Boxplot across levels of a factor
> 
> 
> On Tue, 24 Aug 2004, Paul Boutros wrote:
> 
> > Hello,
> > 
> > I have a data-frame in which one-column is a factor:
> > 
> > > str(data);
> > `data.frame':   194 obs. of  8 variables:
> >  $ Type         : Factor w/ 3 levels "Nuclear-Rec..",..: 1 2 2 
> 2 2 2 2 2 2 2
> > ...
> >  $ Locus        : num  0.000571 0.004000 0.001429 0.004857 0.007429 ...
> > 
> > And I'd like to make a boxplot of the data$Locus values, where 
> each level of
> > the factor gets its own box-and-whiskers plot.  I'm weak in R, 
> but I thought
> > there might be some shortcut to automating this instead of just 
> creating a
> > new data-structure with all the separate values?
> 
> There are two.  The simpler is
> 
> 	boxplot(Locus ~ Type, data=data)
> 
> and you can also use
> 
> 	with(data, boxplot(split(Locus, Type)))
> 
> (split() does automate the construction of a suitable data structure.)
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>