Steven D'Aprano wrote: >> and what exactly does the fact that Python can do operator-based >> dispatch much faster than it can do method-based dispatch have to >> do with sum's inability to add strings ? > > Sorry, I don't get you here. Are you saying that string addition doesn't > call the operands' __add__ methods?
the "+" instruction (BINARY_ADD) special-cases integers and 8-bit strings, and uses a single C call via a type slot for other types. in contrast, "join" and "sum" needs to do a full name lookup and a full Python-level function call. compared to the effort needed to copy 100 bytes, that's a rather expensive set of operations. </F> -- http://mail.python.org/mailman/listinfo/python-list
