On 9/16/07, Guido van Rossum <[EMAIL PROTECTED]> wrote: > I think it's not so obvious that reversing the order is any better > when you throw in some if clauses: > > [friend for city in cities if city.name != "Amsterdam" for friend in > city.friends if friend.name != "Guido"] > > vs. > > [friend for friend in city.friends if friend.name != "Guido" for city > in cities if city.name != "Amsterdam"] > > --Guido >
I think that it's still better, at least if you add some newlines: [friend (Ok, we are talking about a list of friends. From where do these friends come from?) for friend in city.friends if friend.name != "Guido" (Ah, they are all the friends in a city who aren't called Guido. What about the city?) for city in cities if city.name != "Amsterdam"] (Ah, the city is every city which isn't Amsterdam.) Versus: [friend (Ok, we are talking about a list of friends. From where do these friends come from?) for city in cities if city.name != "Amsterdam" (What do cities which aren't Amsterdam have to do with my friend?) for friend in city.friends if friend.name != "Guido"] (Ah, we're talking about all the friends in those cities who aren't called Guido. Let's have a look at the first line to remember what we do with them... ah, yes, we just return them...) Noam _______________________________________________ Python-3000 mailing list Python-3000@python.org http://mail.python.org/mailman/listinfo/python-3000 Unsubscribe: http://mail.python.org/mailman/options/python-3000/archive%40mail-archive.com
