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dinglehopper/src/dinglehopper/align.py

66 lines
1.7 KiB
Python

import math
import unicodedata
from math import ceil
from typing import Optional
from rapidfuzz.distance import Levenshtein
from uniseg.graphemecluster import grapheme_clusters
def align(t1, t2):
"""Align text."""
s1 = list(grapheme_clusters(unicodedata.normalize("NFC", t1)))
s2 = list(grapheme_clusters(unicodedata.normalize("NFC", t2)))
return seq_align(s1, s2)
def score_hint(er: float, n: int) -> Optional[int]:
"""Calculate RapidFuzz score hint for a given error rate and count.
Gives the score hint for the distance functions (= expected distance) or None if
the error rate is inf.
"""
assert not math.isnan(er)
try:
score_hint = int(ceil(er * n))
except (OverflowError, ValueError):
# ceil(er * n) can be inf or NaN (for n == 0), so int() can throw an
# OverflowError and a ValueError.
score_hint = None
return score_hint
def seq_align(s1, s2, score_hint=None):
"""Align general sequences."""
s1 = list(s1)
s2 = list(s2)
ops = Levenshtein.editops(s1, s2, score_hint=score_hint)
i = 0
j = 0
while i < len(s1) or j < len(s2):
o = None
try:
ot = ops[0]
if ot[1] == i and ot[2] == j:
del ops[0]
o = ot
except IndexError:
pass
if o:
if o[0] == "insert":
yield None, s2[j]
j += 1
elif o[0] == "delete":
yield s1[i], None
i += 1
elif o[0] == "replace":
yield s1[i], s2[j]
i += 1
j += 1
else:
yield s1[i], s2[j]
i += 1
j += 1