Message-ID: <47580C7A.6040500@stats.uwo.ca>
Date: 2007-12-06T14:51:38Z
From: Duncan Murdoch
Subject: $ operator is invalid for atomic vectors, returning NULL - what is the right thing to do then?
In-Reply-To: <C83C5E3DEEE97E498B74729A33F6EAEC0562F999@DJFPOST01.djf.agrsci.dk>
On 12/6/2007 7:04 AM, S?ren H?jsgaard wrote:
> Dear all,
> Starting from a recent version of R, the $ became "unusable" on atomic vectors, e.g.
>> x <- c(a=1,b=2)
>> x$a
> NULL
> Warning message:
> In x$a : $ operator is invalid for atomic vectors, returning NULL
>
> I can of course do
>> x['a']
> - but that requires more typing (5 characters rather than 2).
>
> Apologies if I've missed a an announcement regarding this, but
> 1) Is there an alternative to the ['a'] and
> 2) Why was this change made?
There's an announcement in the NEWS file for 2.6.0
DEPRECATED & DEFUNCT
o $ on an atomic vector now gives a warning that it is 'invalid'.
It remains deprecated, but may be removed in R >= 2.7.0.
and an update in R-devel saying that in fact it has been made defunct there.
In answer to your questions:
1) I don't think so, other than x[1].
2) I don't remember the details, other than it was to avoid confusion.
Maybe someone else can summarize the discussion?
Duncan Murdoch