[Rd] is.vector(...) <-> is(..., "vector")

[Prof Brian Ripley]

On Thu, 30 Dec 2004 Matthias.Kohl at uni-bayreuth.de wrote:

> Is it intended that is.vector(...) and is(..., "vector")
> do not always give identical results?

Yes.  What makes you think they are anything to so with each other?
The S4 class "vector" is quite distinct from the usage in base R.

> is.vector() works as documented ('is.vector' returns
> 'FALSE' if 'x' has any attributes except names.)
> Thus,
>
> A <- array(1:2, 1:2)
> M <- diag(2)
>
> is.vector(M) # FALSE, as documented
> # and
> is.vector(A) # FALSE, as documented
>
> # however
> is(M, "vector") # TRUE
> is(A, "vector") # TRUE
>
> # which is also correct, since
> extends("matrix", "vector")
> extends("array", "vector")
>
> I'm working with R Version 2.0.1 Patched (2004-12-09)
> on Windows 2000.

-- 
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)
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