[Rd] Subsetted 1-D arrays (PR#4110)

David Brahm brahm at alum.mit.edu
Wed Oct 22 00:25:50 MEST 2003

In R-patched_2003-10-20, subsetted 1-D arrays no longer get converted to
vectors.  The NEWS file documents this change, as an indirect result of bug
report 4110.  I just wanted to mention this can break code in some rather
obscure ways, such as this toy example:

  R> x <- sort(tapply(1:8, rep(1:4,2), sum))  # Was vector, now is 1D array
  R> y <- matrix(1:4, 1,4)                    # 1x4 matrix
  R> x + y                                    # Used to return a 1x4 matrix
     Error in x + y : non-conformable arrays

I agree with the change, but I would beware that some puzzled users may not
associate new "tapply problems" with this news item.

Also, *should* you be able to add a (4) array to a (1,4) array?
                              -- David Brahm (brahm at alum.mit.edu)

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