On Wed, Jul 04, 2018 at 08:32:32PM +0200, Sven R. Kunze wrote: > >>while total != (total := total + term): > >> term *= mx2 / (i*(i+1)) > >> i += 2 > >>return total > > This very example here caught my eye. > > Isn't total not always equal to total? What would "regular" Python have > looked like?
Read the Appendix to the PEP: https://github.com/python/peps/blob/master/pep-0572.rst And no, total is not always not equal to total. When total and term are sufficiently different, total+term underflows to just total, and the loop exits. py> total = 1.5e30 py> term = 12.5 py> total + term != total False I read it as: while total != updated total: do stuff and find it easier to follow than having to juggle the extra book-keeping "old" variable in the original code. YMMV. -- Steve _______________________________________________ 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
