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Add tool to calculate string distance

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nemunaire 2015-07-24 22:51:47 +02:00
commit 2b0593a51e
2 changed files with 41 additions and 0 deletions
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nemubot/tools/human.py
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@ -36,3 +36,25 @@ def size(size, unit=True):
return "%.3f %s" % (size / math.pow(1024,p), units[int(p)])
else:
return "%.3f" % (size / math.pow(1024,p))
def word_distance(str1, str2):
"""Perform a Damerau-Levenshtein distance on the two given strings"""
d = [[i + j for j in range(len(str2) + 1)] for i in range(len(str1) + 1)]
for i in range(0, len(str1)):
for j in range(0, len(str2)):
cost = 0 if str1[i-1] == str2[j-1] else 1
d[i+1][j+1] = min(
d[i][j+1] + 1, # deletion
d[i+1][j] + 1, # insertion
d[i][j] + cost, # substitution
)
if i >= 1 and j >= 1 and str1[i] == str2[j-1] and str1[i-1] == str2[j]:
d[i+1][j+1] = min(
d[i+1][j+1],
d[i-1][j-1] + cost, # transposition
)
return d[len(str1)][len(str2)]