Hi Martti, On 11.10.2016 14:42, Martti Kühne wrote:
Hello listI love the "new" unpacking generalisations as of pep448. And I found myself using them rather regularly, both with lists and dict. Today I somehow expected that [*foo for foo in bar] was equivalent to itertools.chain(*[foo for foo in bar]), which it turned out to be a SyntaxError. The dict equivalent of the above might then be something along the lines of {**v for v in dict_of_dicts.values()}. In case the values (which be all dicts) are records with the same keys, one might go and prepend the keys with their former keys using { **dict( ("{}_{}".format(k, k_sub), v_sub) for k_sub, v_sub in v.items() ) for k, v in dict_of_dicts.items() } Was anyone able to follow me through this?
Reading PEP448 it seems to me that it's already been considered: https://www.python.org/dev/peps/pep-0448/#variations
The reason for not-inclusion were about concerns about acceptance because of "strong concerns about readability" but also received "mild support". I think your post strengthens the support given that you "expected it to just work". This shows at least to me that the concerns about readability/understandability are not justified much.
Personally, I find inclusion of */** expansion for comprehensions very natural. It would again strengthen the meaning of */** for unpacking which I am also in favor of.
Cheers, Sven _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
