On Monday 20 October 2003 03:22 pm, Nick Coghlan wrote: ...
sum of x*x for x in xvalues average of g for g in grades maximum of f(x, y) for x in xrange for y in yrange top(10) of humour(joke) for joke in comedy ... "from __future__ import"). It's SO beautiful, SO pythonic, the only risk I can see is that we'd have newbie people coding: sum of the_values rather than: sum(the_values) or: sum of x for x in the_values
Except, if it was defined such that you wrote: sum of [x*x for x in the_values]
then: sum of the_values
would actually be a valid expression, and Greg's examples would become:
Yes, you COULD extend the syntax from Greg's NAME 'of' listmaker to _also_ accept NAME 'of' test or thereabouts (in the terms of dist/src/Grammar/Grammar of course), I don't think it would have any ambiguity. As to whether it's worth it, I dunno.
sum of xvalues
Nope, he's summing the _squares_ -- sum of x*x for x in xvalues it says.
average of grades
Yes, this one would then work.
maximum of [f(x, y) for x in xrange for y in yrange]
Yes, you could put brackets there, but why?
top(10) of [humour(joke) for joke in comedy]
Ditto -- and it doesn't do the job unless the magic becomes even blacker. top(N) is supposed to return jokes, not their humor values; so it needs to get an iterable or iterator of (humor(joke), joke) PAIRS -- I think it would DEFINITELY be better to have this spelled out, and in fact I'd prefer: top(10, key=humour) of comedy or top(10, key=humour) of joke for joke in comedy using the same neat syntax "key=<callable>" just sprouted by lists' sort method.
Either way, that's some seriously pretty executable psuedocode he has happening! And a magic method "__of__" that takes a list as an argument might be enough to do the trick, too.
Agreed on the prettiness. I would prefer to have the special method be defined to receive "an iterator or iterable" -- so we can maybe put together a prototype where we just make and pass it a list, BUT keep the door open to passing it an "iterator comprehension" in the future. Or maybe make it always an iterator (in the prototype we can just build the list and call iter on it anyway... so it's not any harder to get started playing with it). Oh BTW, joining another still-current thread -- for x in sorted_copy of mylist: ... now doesn't THAT read just wonderfully, too...?-) Alex