[Rd] string-length limitations

[jake wilson]

Thank you - the proposed solution (eliminating quotes) worked.


>From: Prof Brian Ripley <ripley at stats.ox.ac.uk>
>To: jake wilson <jake_f_wilson at hotmail.com>
>CC: r-devel at r-project.org
>Subject: Re: [Rd] string-length limitations
>Date: Wed, 12 Jul 2006 15:38:22 +0100 (BST)
>
>On Wed, 12 Jul 2006, jake wilson wrote:
>
> > Hi,
> >
> > I'm attempting to "glm" a formula - something that's not caused problems 
>in
> > the past.  I've used formulas of the form
> >
> >     formula( "dependant-variable~independant-variables" )
> >
> > where the independant variable string is of the form:
> >
> >     "indvar1+indvar2+...+indvarN"
>
>Why the quotes?: I think that is your problem.
>
> > Now, however, our independant variable strings are quite long (hundreds 
>of
> > variables) - R dies with an "input buffer overflow" error.
>
>It is normal to use (y ~ ., data=mydata) to avoid such formulae.
>
> >  I've tried writing out the code to files and sourcing them, as well as
> > building the strings incrementally in R, but these have not worked
> > either.  I have come to believe there is a maximum length for char
> > strings - some sort of fundamental limitation.  Is there such a
> > max-length and, if so, is there a way I can work with long strings of
> > the sort referenced above?
>
>The limit is 2^31 -1, not relevant here.
>
>Your message is coming from the parser, and suggests that it is trying to
>parse a piece of text longer than MAXELTSIZE bytes.  The latter depends on
>the platform (unstated: do see the posting guide) and is often 8196 bytes.
>So there is a limit on the length of quoted strings which can be input.
>
>However, what is wrong with say
>
>tmp <- paste(paste("indvar", 1:1000, sep=""), collapse="+")
>tmp <- paste("y ~", tmp)
>form <- eval(parse(text=tmp))
>
>?
>
>--
>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