python-string-similarity/similarity/jaccard.py

from .shingle_based import ShingleBased
from .string_distance import NormalizedStringDistance, MetricStringDistance
from .string_similarity import NormalizedStringSimilarity


class Jaccard(ShingleBased, MetricStringDistance, NormalizedStringDistance, NormalizedStringSimilarity):

    def __init__(self, k):
        super().__init__(k)

    def distance(self, s0, s1):
        1.0 - self.similarity(s0, s1)

    def similarity(self, s0, s1):
        if s0 is None:
            raise TypeError("Argument s0 is NoneType.")
        if s1 is None:
            raise TypeError("Argument s1 is NoneType.")
        if s0 == s1:
            return 1.0
        if len(s0) < self.get_k() or len(s1) < self.get_k():
            return 0.0
        profile0 = self.get_profile(s0)
        profile1 = self.get_profile(s1)
        union = set()
        for ite in profile0.keys():
            union.add(ite)
        for ite in profile1.keys():
            union.add(ite)
        inter = int(len(profile0.keys()) + len(profile1.keys()) - len(union))
        return 1.0 * inter / len(union)