On Wed, 3 May 2023 at 18:52, Thomas Passin <li...@tompassin.net> wrote: > > On 5/3/2023 5:45 AM, fedor tryfanau wrote: > > I've been using python as a tool to solve competitive programming problems > > for a while now and I've noticed a feature, python would benefit from > > having. > > Consider "reversed(enumerate(a))". This is a perfectly readable code, > > except it's wrong in the current version of python. That's because > > enumerate returns an iterator, but reversed can take only a sequence type. > > Depending on what you want to give and receive, enumerate(reversed(a)) > will do the job here. Otherwise list() or tuple() can achieve some of > the same things.
I don't think that is equivalent to the intended behaviour: reversed(enumerate(a)) # zip(reversed(range(len(a))), reversed(a)) enumerate(reversed(a)) # zip(range(len(a)), reversed(a)) In principle for a sequence input enumerate(a) could be something that behaves like a sequence and therefore could be reiterated or reversed etc. The enumerate(a).__reversed__ method could then delegate to a.__reversed__ and a.__len__ if they exist. This could be confusing though because the possible behaviour of enumerate(a) would be different depending on the type of a. -- Oscar -- https://mail.python.org/mailman/listinfo/python-list
