[R] checking for identical columns in a mxn matrix

[Rajarshi Guha]

Hi,
  I have a rectangular matrix and I need to check whether any columns
are identical or not. Currently I'm looping over the columns and
checking each column with all the others with identical().

However, as experience has shown me, getting rid of loops is a good idea
:) Would anybody have any suggestions as to how I could do this job more
efficiently.

(It would be nice to know which columns are identical but thats not a
necessity.)

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Rajarshi Guha <rxg218 at psu.edu> <http://jijo.cjb.net>
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