[R] dimnames

[Prof Brian D Ripley]

On Sun, 14 Nov 1999 cstrato at EUnet.at wrote:

> Maybe this is a simple question:
> 
> Using S-Plus, and having a matrix m with row- and col-names, I have the
> following problem:
> 
> When I import into a function the one-column matrix m[,i], I am no
> longer able to get the
> column name. Is there a way to get the column-name?
> 
> (Although attributes(m) displays row- and col-names, attributes(m[,i])
> does no longer show
> the col-name.)

If i is a single number, m[, i] is not a matrix but a vector. You need
m[,i, drop=F] to preserve it as a one-column matrix.

You can use dimnames() to see the column names, or colnames() in R.

I am not sure why you sent an S-PLUS question to R-help: would not S-news
be more appropriate?  (Because of the presence of colnames() in R, the
answer might be subtly different.)

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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