[Tutor] Aschenputtel problem
Roel Schroeven
rschroev_nospam_ml at fastmail.fm
Thu Sep 15 23:33:15 CEST 2005
Alan Gauld schreef:
>>I wonder if there is a shorter form of the following idiom:
>
>
> Bearing in mind that shorter is not necessarily better...
>
> [condition(i) and list1.append(i) or list2.append(i) for i in
> original]
Alas, won't work. This is one of the cases where the ... and ... or ...
idiom doesn't work; this is why I don't like it and don't use it. The
problem is that list1.append(i) returns None, so list2.append(i) is
always called, even if list1.append(i) was already called:
>>> list1 = []
>>> list2 = []
>>> False and list1.append(2) or list2.append(2)
>>> list1, list2
([], [2])
>>> True and list1.append(4) or list2.append(4)
>>> list1, list2
([4], [2, 4])
--
If I have been able to see further, it was only because I stood
on the shoulders of giants. -- Isaac Newton
Roel Schroeven
More information about the Tutor
mailing list