R devel - May 2006 - Problem with pasteing formulas (PR#8897)

Hi,
If I create a formula with say 100 terms and then paste it:

xnam <- paste("x", 1:100, sep="")
fmla <- as.formula(paste("y ~ ", paste(xnam, collapse=
"+")))
paste(fmla)

The result seems to cut off everything after the first 500 characters 
and gives no warning message.

I have the most recent version of R from the R website and the problem 
occurs on both Unix and Windows machines

Thanks

John
-- 
John Little
Department of Mathematical Sciences
Durham University
Durham
UK

See ?as.character (which paste effectively calls on non-character objects, 
as ?paste says):

Note:

      'as.character' truncates components of language objects to 500
      characters (was about 70 before 1.3.1).

so it is working as documented.  Not then a bug.

You can (and probably should) use a construct like that in terms.formula:

         else paste(deparse(form[[2]]), collapse = "")

to convert a formula to a complete character string.


On Wed, 24 May 2006, john.little at dunelm.org.uk wrote:
> Hi,
> If I create a formula with say 100 terms and then paste it:
>
> xnam <- paste("x", 1:100, sep="")
> fmla <- as.formula(paste("y ~ ", paste(xnam, collapse=
"+")))
> paste(fmla)
>
> The result seems to cut off everything after the first 500 characters
> and gives no warning message.
>
> I have the most recent version of R from the R website and the problem
> occurs on both Unix and Windows machines
>
> Thanks
>
> John
>
-- 
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