R devel - Oct 2001 - NA as names of vector from subscripted matrix == bug ?

Is this a bug?
> matrix(1:4,nc=2,dimnames=list(1:2,1:2))[c(1,3)]
 1 NA 
 1  3 

It has some annoying consequences, e.g.
> median( matrix(1:9,nc=3,dimnames=list(1:3,1:3))[1,,drop=F] )
NA 
 4 
> 
The above was for 

Version:
 platform = sparc-sun-solaris2.7
 arch = sparc
 os = solaris2.7
 system = sparc, solaris2.7
 status = 
 major = 1
 minor = 3.0
 year = 2001
 month = 06
 day = 22
 language = R


The behavior seems to differ slightly in 1.3.1.

On Windows 1.3.1  

 matrix(1:9,nc=3,dimnames=list(1:3,1:3))[ cbind(1:3,1:3) ]

omits the names (as is my preference).

 
Charles C. Berry                        (858) 534-2098 
                                         Dept of Family/Preventive Medicine
E mailto:cberry@tajo.ucsd.edu	         UC San Diego
http://hacuna.ucsd.edu/members/ccb.html  La Jolla, San Diego 92093-0645

 

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On Mon, 8 Oct 2001, Charles C. Berry wrote:
>
> Is this a bug?
>
> > matrix(1:4,nc=2,dimnames=list(1:2,1:2))[c(1,3)]
>  1 NA
>  1  3

Perhaps a clearer example is
> matrix(1:4,nc=2,dimnames=list(LETTERS[1:2],LETTERS[3:4]))->a
> a[1]
A
1
> a[2]
B
2
> a[3]
NA
 3
> a[4]
NA
 4
>
It's at least a wart that you sometimes get the row names and sometimes
NA.  OTOH it's not clear what the names of a vector extracted from a
matrix *should* be if the vector isn't a single row or column.



	-thomas


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