Nulls being coerced : Bug or design?

Well, feel free to make up any semantics that you like for a language
you write, but R already has its own and tells you what to expect:

From ?NULL:

NULL can be indexed (see Extract) in just about any syntactically
legal way: whether is makes sense or not, the result is always NULL.
Objects with value NULL can be changed by replacement operators and
will be coerced to the type of the right-hand side.

Cheers,
Bert

On Fri, Jun 21, 2013 at 1:21 PM, Saptarshi Guha

Hello,

Consider the following transcript

x=NULL
x$date=10
x

$date
[1] 10

or

x=NULL
x[10]=10
x

 [1] NA NA NA NA NA NA NA NA NA 10


Wouldn't one expect that x remain NULL despite the further additions (i.e
the x$date, x[10]) etc? Is coercing appropriate here?

Cheers
Saptarshi

        [[alternative HTML version deleted]]

______________________________________________
R-help at r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Bert Gunter
Genentech Nonclinical Biostatistics

Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm