Xiang Zhang added the comment: > You can use operator.add() if you need to fall back to a __radd__ of the > right operand.
IMHO for sequences when defining __add__, __radd__, there is no difference between addition and concatenation, just as https://docs.python.org/3/reference/datamodel.html#emulating-container-types states. So it's confusing for me why must I use operator.add not operator.concate? > operator.concat() is Python API to the sq_concat slot. It falls back to > __add__() just because instances of user classes defining an __add__() method > only have an nb_add slot, not an sq_concat slot. More like a implementation detail for me. Users writing only Python won't realize such things. > Third-party classes (maybe NumPy arrays, I don't know) can have different > implementations of sq_concat and nb_add. Does this matter? Anyway operator.concat will fall to '+'. My intent is proposing something like: if not hasattr(a, '__getitem__') and not hasattr(b, '__getitem__') ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue29139> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
