On May 18, 11:31 am, Tim Hoffman <zutes...@gmail.com> wrote: > Hi Marco > > Thats definately what I think is happening. > > I tried the following > > >>> class yy(object): > > ... def __getitem__(self,name): > ... raise KeyError(name) > ... def __contains__(self,name): > ... raise KeyError(name) > ...>>> aa = yy() > >>> 'll' in aa > > Traceback (most recent call last): > File "<stdin>", line 1, in ? > File "<stdin>", line 5, in __contains__ > KeyError: 'll'>>> [i in aa] > > Traceback (most recent call last): > File "<stdin>", line 1, in ? > NameError: name 'i' is not defined>>> [i for i in aa] > > Traceback (most recent call last): > File "<stdin>", line 1, in ? > File "<stdin>", line 3, in __getitem__ > KeyError: 0 > > > > Which suggests to me there must be some sort of order of precedence > between __contains__ and __getitem__ > and 'for' statement must change the order in some manner. > > Thanks for the reply > > T > > On May 18, 11:24 pm, Marco Mariani <ma...@sferacarta.com> wrote: > > > timh wrote: > > > However strange things happen to the name passed to __getitem__ in the > > > following example (and in fact in all varients I have triend the name/ > > > key passed to __getitem__ is always the integer 0 > > > I think it's scanning the container as a sequence and not as a mapping, > > hence the access by index. > >
Whoops, I just realized I posted the wrong link... http://docs.python.org/reference/expressions.html#in Jeff -- http://mail.python.org/mailman/listinfo/python-list
