R help - Jul 2010 - Matrix Column Names

Hi,

Is there a way to create a matrix in which the column names are not
checked to see if they are valid variable names?

I'm looking something similar to the check.names argument to
data.frame.  If so, would such an approach work for the sparse matrix
classes in the Matrix package.

Many thanks!

Cheers,
Dave

>>>>> "DN" == David Neu <david at davidneu.com>
>>>>>     on Mon, 12 Jul 2010 18:15:04 -0400 writes:
    DN> Hi, Is there a way to create a matrix in which the
    DN> column names are not checked to see if they are valid
    DN> variable names?

Why do you need that if you are really using a matrix, not a
data frame?

    DN> I'm looking something similar to the check.names
    DN> argument to data.frame.  

That's a good idea.
The relevant code inside data.frame() is simply

    if (check.names) 
        vnames <- make.names(vnames, unique = TRUE)

    DN> If so, would such an approach work for the sparse matrix
    DN> classes in the Matrix package.

Using function  make.names(), yes of course.

{but I'm still puzzled *why* you need this;
 If you want only want somewhat *short* names,
 I'd rather use

    vnames <- abbreviate(vnames, 8)

or variations of that such as
    vnames <- abbreviate(vnames, 8, method="both.sides")
or also
    vnames <- abbreviate(vnames, 8, strict=FALSE)

    DN> Many thanks!

you're welcome!

Martin Maechler, ETH Zurich