[Rd] is.matrix
Wacek Kusnierczyk
Waclaw.Marcin.Kusnierczyk at idi.ntnu.no
Tue Nov 11 20:42:08 CET 2008
hadley wickham wrote:
>> | is.matrix| returns |TRUE| if |x| is a matrix and has a |dim <dim.html>|
>> attribute of length 2) and |FALSE| otherwise
>>
>
> That's confusing! In what situations is x a matrix but does not have
> a dim attribute?
>
>
x = matrix(1,1,1)
dim(x) = c(1,1,1)
is.matrix(x)
# no
is("matrix", x)
# no
is(x)
# hm...
following the last, there would be a situation in which an object is a
matrix (per is(...)) and has a dim attribute of length != 2, but is a
matrix (per is.matrix(...) and is("matrix", ...), consistently with the
docs).
(the redundant "vector" in is(x) could probably be removed?)
vQ
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