Method Ck

pattern/vector/__init__.py:1220–1228

For the given sets of length k, returns combined candidate sets of length k+1.

(self, sets)

        return [frozenset([v]) for v in set(chain(*sets))]

    def Ck(self, sets):
        """ For the given sets of length k, returns combined candidate sets of length k+1.
        """
        Ck = []
        for i, s1 in enumerate(sets):
            for j, s2 in enumerate(sets[i+1:]):
                if set(list(s1)[:-1]) == set(list(s2)[:-1]):
                    Ck.append(s1 | s2)
        return Ck
        
    def Lk(self, sets, candidates, support=0.0):
        """ Prunes candidate sets whose frequency < support threshold.