cute and interesting. On Sat, Dec 17, 2011 at 6:27 PM, Ram Rachum <[email protected]> wrote: > On Sat, Dec 17, 2011 at 6:14 PM, Shai Berger <[email protected]> wrote: >> >> > >> > (Note that these are the only commands that I ran. You're not allowed to >> > run any other commands before them.) >> > >> > The riddle: What's the shortest thing you can put instead of *???* so my >> >> > second command would not raise an exception? >> > >> > >> ???= (yield) >> >> right? >> >> (mailed privately, to avoid ruining the fun...) > > > Yep!!! I just almost finished writing the email to tell everyone that when I > got your answer. > > Congrats for solving the riddle Shai. > > So as Shai said, the solution is: > >> >> >>> f = lambda: g((yield)) >> >>> f() > > > Funny, isn't it? I was surprised to see that the `yield` keyword can be used > in a lambda function. > > So when you type `f()`, it just returns a generator. If you'll try to > exhaust it, an exception will be raised because `g` doesn't exist, but > that's a new line :) > > It's funny that in this case, Python seems to throw away the value of the > lambda function! As we know, the `yield` keyword actually forms a statement > whose value is `None`, unless you used the generator's `.send` instead of > `.next`. So you could also use `.send` to send in whatever value you want > into the lambda function, and Python will just throw it away. Unless I'm > missing something. > > So that's the only case I can think of where Python completely throws away > the value of a lambda function. > > > Another funny thing that I learned from this riddle is that when you do a > function invocation in Python, Python accesses the function before it looks > at the arguments. > > So if were to do: > >> adfgadgof(1 / 0) > > > Python will complain about the non-existent function before it even sees the > division-by-zero. > > _______________________________________________ > Python-il mailing list > [email protected] > http://hamakor.org.il/cgi-bin/mailman/listinfo/python-il >
-- Alon Levy _______________________________________________ Python-il mailing list [email protected] http://hamakor.org.il/cgi-bin/mailman/listinfo/python-il
