2015-11-23 7:21 GMT+01:00 Alexander Walters <tritium-l...@sdamon.com>: > collections.Counter.__add__ as a bit of a quirk. > > Counters allow for negative numbers. You can subtract from a counter into > the negative no problem. However, if you have a counter with a negative > value and add it to another counter, and if that value, after addition, > would still be negative... that value is not included in the resulting > Counter object. This is kind of weird, to the point of thinking I had a bug > in other code for several hours until I went and checked how Counters are > implemented. > > Is there any particular reason counters drop negative values when you add > them together? I definitely expected them to act like ints do when you add > negatives, and had to subclass it to get what I think is the obvious > behavior. > _______________________________________________ > Python-Dev mailing list ... Hi, this is probably more appropriate for the general python list rathere then this developers' maillist, however, as I asked a similar question some time ago, I got some detailed explanations for the the current design decissions from the original developer; cf.: https://mail.python.org/pipermail/python-list/2010-March/570618.html
(I didn't check possible changes in Counter since that version (3.1 at that time).) hth, vbr _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
