[R] character string to name
Prof Brian Ripley
ripley at stats.ox.ac.uk
Tue Jul 10 09:00:24 CEST 2007
On Mon, 9 Jul 2007, Thomas Lumley wrote:
> On Mon, 9 Jul 2007, Jim Lemon wrote:
>> Hi folks,
>> I thought I recalled a request for turning a character string into an
>> object name as in:
> Yes. It's a FAQ.
There is an FAQ about turning character strings into objects (Q7.21), but
this seems a bit different. In the first example, he really does want a
name. Since $ does not evaluate its rhs, ways to do that are
yy <- "y"
x$[[yy]] <- 1:4
eval(substitute(x$yy <- 1:4, list(yy=yy)))
and of course parse(text=).
For the second, I think something like
e <- quote(data.frame(yy=1:4))
names(e) <- yy
x <- eval(e)
is probably the simplest way.
>> However, as.name and a few other uninformed attempts didn't even come
>> close. A search of "character to name" produced no helpful functions.
>> This isn't a very urgent request, but if anyone knows some trick to
>> perform this transformation, I would like to hear about it. Thanks.
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
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