R help - Apr 1999 - math mode in box plots

Here is another of those 'is it a bug or am I using it wrong'
questions:  I'd be very grateful if someone could help.

I am doing a lot of graphs for a thesis at the minute, many of which need
(ideally) greek letters in xlab and ylab.

This works:
>plot(c(1,2,3,4),c(1,2,3,4),xlab=expression( alpha * "-1-m"))
>
This does not:
> boxplot(c(1,2,3,4),c(1,2,3,4),xlab=expression( alpha * "-1-m"))
Error: Object "alpha" not found
> 
Tried it on both 0.63 and 0.64 with same result.
Any help much appreciated:  the scatterplots look so much better with the
proper greek.

Regards,

Michael Lapsley
----------------------------------
E-Mail: Michael Lapsley <mlapsley at ndirect.co.uk>
Date: 20-Apr-99
Time: 00:23:47

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Michael Lapsley <mlapsley at ndirect.co.uk> writes:
> Here is another of those 'is it a bug or am I using it wrong'
...
> This works:
> >plot(c(1,2,3,4),c(1,2,3,4),xlab=expression( alpha * "-1-m"))
> >
> 
> This does not:
> > boxplot(c(1,2,3,4),c(1,2,3,4),xlab=expression( alpha *
"-1-m"))
> Error: Object "alpha" not found
It's a bug (apparently of the same flavor as using eval(x) to force
lazy evaluation - which works only if x is not an expression):
> title(xlab=expression(alpha*"-1-m")) # OK
> args<-list(xlab=expression(alpha*"-1-m"))
> do.call("title",args)
Error: Object "alpha" not found

Thanks for pointing it out. For a workaround, try plotting the boxplot
without the xlab, then add the xlab using title() directly.


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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