

   MMaattrriixx TTrraannssppoossee

        t(x)

   DDeessccrriippttiioonn::

        Given a matrix or `data.frame' `x', `t' returns the
        transpose (matrix or data.frame) of `x'.

   EExxaammpplleess::

        a <- matrix(1:30, 5,6)
        ta <- t(a) ##-- i.e.,  a[i,j] == ta[j,i] for all i,j :
        for(j in seq(ncol(a)))
          if(! a[,j] == ta[j,]) stop("wrong transpose")

