Message408622
Here I propose a new function, namely .ratio_min(self,m).
.ratio_min(self,m) is an extension of the difflib's function .ratio(self). Equivalently to .ratio(self), .ratio_min(self,m) returns a measure of two sequences' similarity (float in [0,1]). In addition to .ratio(), it can ignore matched substrings if these substrings have length less than a given threshold m. m is the second variable of the function.
It is very useful to avoid spurious high similarity scores.
# NEW FUNCTION:
def ratio_min(self,m):
"""Return a measure of the sequences' similarity (float in [0,1]).
Where T is the total number of elements in both sequences, and
M_min is the number of matches with every single match has length at least m, this is 2.0*M_min / T.
Note that this is 1 if the sequences are identical, and 0 if
they have no substring of length m or more in common.
.ratio_min() is similar to .ratio().
.ratio_min(1) is equivalent to .ratio().
>>> s = SequenceMatcher(None, "abcd", "bcde")
>>> s.ratio_min(1)
0.75
>>> s.ratio_min(2)
0.75
>>> s.ratio_min(3)
0.75
>>> s.ratio_min(4)
0.0
"""
matches = sum(triple[-1] for triple in self.get_matching_blocks() if triple[-1] >=m)
return _calculate_ratio(matches, len(self.a) + len(self.b)) |
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2021-12-15 17:37:14 | gibu | set | recipients:
+ gibu |
2021-12-15 17:37:14 | gibu | set | messageid: <1639589834.45.0.869314940446.issue46086@roundup.psfhosted.org> |
2021-12-15 17:37:14 | gibu | link | issue46086 messages |
2021-12-15 17:37:14 | gibu | create | |
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