From Matthias.Kohl at uni-bayreuth.de  Thu Dec 30 11:09:50 2004
From: Matthias.Kohl at uni-bayreuth.de (Matthias.Kohl@uni-bayreuth.de)
Date: Thu Dec 30 11:09:54 2004
Subject: [Rd] is.vector(...) <-> is(..., "vector")
Message-ID: <1223.132.180.246.67.1104401390.squirrel@mail.uni-bayreuth.de>

Hello,

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

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.

Thanks, for any comments!
Matthias


[Rd] is.vector(...) <-> is(..., "vector")
Matthias.Kohl@uni-bayreuth.de