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

Matthias.Kohl at uni-bayreuth.de Matthias.Kohl at uni-bayreuth.de
Thu Dec 30 11:09:50 CET 2004


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



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