is.matrix

a <- c(1, 1, 2)
class(a)

ta <- t(a)
class(ta)

class(t(ta))

-----Original Message-----
From: r-devel-bounces at r-project.org 
[mailto:r-devel-bounces at r-project.org] On Behalf Of Daniel 
H?yer Iversen
Sent: Tuesday, November 11, 2008 2:36 PM
To: hadley wickham
Cc: Tony Plate; r-devel at r-project.org
Subject: Re: [Rd] is.matrix

That's confusing!  In what situations is x a matrix but 

does not have 

a dim attribute?

That was my point. I don't find it logical that
is.matrix(a) gives FALSE but
is.matrix(t( t(a) )) gives TRUE.

I also think it would be more logical that
a=c(1,1,2)
dim(a) gives 3 1 instead of NULL,



Daniel



On Tue, Nov 11, 2008 at 8:21 PM, hadley wickham 
<h.wickham at gmail.com> 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?

Hadley

--
http://had.co.nz/