[Rd] Inconsistency when naming a vector

Kevin Ushey kevinushey at gmail.com
Mon Apr 27 15:30:11 CEST 2015

In `?names`:

     If ‘value’ is shorter than ‘x’, it is extended by character ‘NA’s
     to the length of ‘x’.

So it is as documented.

That said, it's somewhat surprising that both NA and "" serve as a
placeholder for a 'missing name'; I believe they're treated
identically by R under the hood (e.g. in subsetting operations) but
there may be some subtle cases where they're not.

On Mon, Apr 27, 2015 at 6:08 AM, Suzen, Mehmet <msuzen at gmail.com> wrote:
> There is no inconsistency. Documentation of `names` says "...value
> should be a character vector of up to the same length as x..."
> In the first definition your character vector is not the same length
> as length of x, so you enforce NA by not defining value[2]
> x <- 1:2
> value<-c("a")
> value[2]
> [1] NA
> where as in the second case, R uses default value "", from `names`
> documentation "..The name "" is special: it is used to indicate that
> there is no name associated with an element.". Since you defined the
> first one, it internally assigns "" to non-defined names to match the
> length of the vector.
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