[R] about the char _

Philippe Grosjean phgrosje at ulb.ac.be
Fri Oct 5 13:51:33 CEST 2001

Well, you are totally right. Backward compatibility *is* very important.
That is probably a reason why the R team keeps _ as a synonym of <- for
assignation. And still, there is the nice function make.names() to eliminate
improper characters from name strings. Yet, I still believe that not using .
(dot) in names strings would easy to decrypt the "object hierarchy" in R as
in Splus. make.names() replaces any improper character by ... a dot. Thus,
you got dots everywhere in variables names when you import data from SAS, or
any external source.

-----Message d'origine-----
De : Patrick Connolly [mailto:P.Connolly at hortresearch.co.nz]
Envoye : vendredi 5 octobre 2001 14:33
A : Philippe Grosjean
Cc : R-help
Objet : Re: [R] about the char _

According to Philippe Grosjean:


|> If _ was allowed in variables names, we could use print.my_var
|> (which should, perhaps, be recommended) and it would be easier to spot
|> is the "object hierarchy" and where is the variable name.

Here is one stick-in-the-mud who does not share the enthusiasm for
such a change.  I started using Splus almost 10 years ago, and being a
confirmed lazy typist ever since I started using unix, I immediately
adopted the '_' shortform instead of the clumsy '<-' sequence.  It's
an ingrained habit now which will be hard for an old codger to get out
of.  Some esteemed contributors to this list have strong feelings
against its use, but for my own use, I don't encounter any problems.
If I make my code public I change it, but at the time of writing it in
the first place, I'm very attached to lazy typing.

There are hundreds of files of code which I have written the lazy way
and I periodically source those.  Perhaps it wouldn't be difficult to
search and replace in those files, but I'd prefer not to edit them
since the date of the files is important information.

Of course, such a stick-in-the-mud attitude does make it difficult to
make progress by insisting on backward compatibility, but I offer a

You could get a similar effect with names such as my..variable which
would be visually distinctive from my.variable and still work with the
current convention, but I don't know if SAS could deal with such a
name. There could be a problem with ..myfun.x1 because it would not be
available to the likes of objects(), but there could well be a way
around that.


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