On 12월14일, 오전2시57분, mattia <ger...@gmail.com> wrote: > Il Sun, 13 Dec 2009 16:37:20 +0000, mattia ha scritto: > > > How can I insert non-duplicate data in a list? I mean, is there a > > particular option in the creation of a list that permit me not to use > > something like: > > def append_unique(l, val): > > if val not in l: > > l.append(val) > > > Thanks, > > Mattia > > Ok, so you all suggest to use a set. Now the second question, more > interesting. Why can't I insert a list into a set? I mean, I have a > function that returns a list. I call this function several times and > maybe the list returned is the same as another one already returned. I > usually put all this lists into another list. How can I assure that my > list contains only unique lists? Using set does'n work (i.e. the python > interpreter tells me: TypeError: unhashable type: 'list')...
this makes the set type hashable. class Set(set): __hash__ = lambda self: id(self) s = Set() s.add(1) s.add(2) s.add(1) print s set([1, 2]) d = {} d[s] = 'voila' print d {Set([1,2]):'voila'} print d[s] 'voila' -- http://mail.python.org/mailman/listinfo/python-list