Assignment operators (was [R] modifying a vector)
Frank E Harrell Jr
Sun, 30 Jun 2002 14:42:49 -0400
On Sun, 30 Jun 2002 18:57:38 +0100 (BST)
> On Sun, 30 Jun 2002, Frank E Harrell Jr wrote:
> > On 30 Jun 2002 09:12:31 -0700
> > "A.J. Rossini" <firstname.lastname@example.org> wrote:
> > > >>>>> "john" == John Fox <email@example.com> writes:
> > >
> > > john> The equal sign has already been provided as an alternative assignment
> > > john> operator in R.
> > >
> > > And I feel the same way about "=" as I do about "_". Yech.
> > I'll second that. And we've already seen the big trouble that can be
> caused by "=" (e.g., mistyping sex=='male' as sex='male') that was not
> envisioned by the developers. -Frank Harrell
> Was that actually in R (where very few people use =)? Unlike S4, = is not
> a general-purpose assignment operator, and this sort of thing *was*
> `envisioned by the developers'. For example, if(sex = "male") is a syntax
> error in R. (Some more insidious ones, such as using assignment in the
> a function call, are also disallowed.)
It was probably S-Plus. I have trouble keeping S-Plus and R separate sometimes.
I hope that R also provides safeguards about "=" when it appears in an argument to a function.
> If there is evidence that this is regularly causing trouble we would want
> to re-consider its scope, but the availability of `=' is hardly publicised
> (and not even the editor of the Programmer's Niche remembered about it).
> (Moved to R-devel, as maybe R-help should be spared this source of
Sure. Thanks Brian -Frank
> Brian D. Ripley, firstname.lastname@example.org
> 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 272860 (secr)
> Oxford OX1 3TG, UK Fax: +44 1865 272595
Frank E Harrell Jr Prof. of Biostatistics & Statistics
Div. of Biostatistics & Epidem. Dept. of Health Evaluation Sciences
U. Virginia School of Medicine http://hesweb1.med.virginia.edu/biostat
r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
Send "info", "help", or "[un]subscribe"
(in the "body", not the subject !) To: email@example.com