On Thu, Sep 30, 2010 at 3:28 AM, Robert Kern <[email protected]> wrote: > On Wed, Sep 29, 2010 at 12:00, Pauli Virtanen <[email protected]> wrote: >> Wed, 29 Sep 2010 11:15:08 -0500, Robert Kern wrote: >> [clip: inplace addition with duplicates] >>> Use numpy.bincount() instead. >> >> It might be worthwhile to add a separate helper function for this >> purpose. Bincount makes a copy that could be avoided, and it is difficult >> to find if you don't know about this trick. > > I'm fairly certain that most of the arrays used are fairly small, as > such things are reckoned. I'm not sure that in-place modification > would win us much. And I'm not sure what other name for the function > would make it easier to find. AFAICT, using bincount() this way is not > really a "trick"; it's just the right way to do exactly this job. If > anything, "x.fill(0);x[i] += 1" is the "trick".
bincount only works for gathering/accumulating scalars. Even the 'weights' parameter is limited to scalars. I propose the name 'gather()' for the helper function that does this. _______________________________________________ NumPy-Discussion mailing list [email protected] http://mail.scipy.org/mailman/listinfo/numpy-discussion
