On Wed, 22 Nov 2017 15:03:09 +0200 Serhiy Storchaka <storch...@gmail.com> wrote: > From > https://stackoverflow.com/questions/45190729/differences-between-generator-comprehension-expressions. > > g = [(yield i) for i in range(3)] > > Syntactically this looks like a list comprehension, and g should be a > list, right? But actually it is a generator. This code is equivalent to > the following code: > > def _make_list(it): > result = [] > for i in it: > result.append(yield i) > return result > g = _make_list(iter(range(3))) > > Due to "yield" in the expression _make_list() is not a function > returning a list, but a generator function returning a generator. > > This change in semantic looks unintentional to me. It looks like leaking > an implementation detail.
Perhaps we can deprecate the use of "yield" in comprehensions and make it a syntax error in a couple versions? I don't see a reason for writing such code rather than the more explicit variants. It looks really obscure, regardless of the actual semantics. Regards Antoine. _______________________________________________ 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
