[Python-Dev] lambda (x, y): (original) (raw)

Brett Cannon brett at python.org
Sun Jan 26 01:01:31 CET 2014

On Sat, Jan 25, 2014 at 12:41 AM, Greg Ewing <greg.ewing at canterbury.ac.nz>wrote:

Brett Cannon wrote:

On Fri, Jan 24, 2014 at 10:50 AM, Ram Rachum <ram at rachum.com <mailto:_ _ram at rachum.com>> wrote: lambda (x, y): whatever http://python.org/dev/peps/pep-3113/ Part of the rationale in that PEP is that argument unpacking can always be replaced by an explicitly named argument and an unpacking assignment. No mention is made of the fact that you can't do this in a lambda, giving the impression that lambdas are deemed second-class citizens that are not worth consideration. The author was clearly aware of the issue, since a strategy is suggested for translation of lambdas by 2to3: lambda (x, y): x + y --> lambda xy: xy[0] + xy[1] That's a bit on the ugly side for human use, though. An alternative would be lambda xy: (lambda x, y: x + y)(*xy) Whether that's any better is a matter of opinion.

As the author of the PEP and I can say that lambda (x, y): x + y can just as easily be expressed as lambda x, y: x + y and then be called by using *args in the argument list. Anything that gets much fancier typically calls for a defined function instead of a lambda. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20140125/fd7e5491/attachment.html>

More information about the Python-Dev mailing list