[Python-Dev] (no subject) (original) (raw)

Ethan Furman ethan at stoneleaf.us
Tue Feb 10 03:10:36 CET 2015

On 02/09/2015 05:48 PM, Donald Stufft wrote:

I don’t think * means “loop” anywhere else in Python and I would never “guess” that [*item for item in iterable] meant that. It’s completely non intuitive. Anywhere else you see *foo it’s unpacking a tuple not making an inner loop. That means that anywhere else in Python *item is the same thing as item[0], item[1], item[2], …, but this PEP makes it so just inside of a comprehension it actually means “make a second, inner loop” instead of what I think anyone who has learned that syntax would expect, which is it should be equivalent to [(item[0], item[1], item[2], …) for item in iterable].

I agree with Donald. I would expect a list of lists from that syntax... or maybe a list of tuples?

-- Ethan

-------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 836 bytes Desc: OpenPGP digital signature URL: <http://mail.python.org/pipermail/python-dev/attachments/20150209/7326bb80/attachment.sig>

More information about the Python-Dev mailing list