Created
March 17, 2016 02:34
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""" | |
python3.5 | |
tongtie | |
""" | |
import time | |
import difflib | |
def normal_leven(str1, str2): | |
len_str1 = len(str1) + 1 | |
len_str2 = len(str2) + 1 | |
#create matrix | |
matrix = [0 for n in range(len_str1 * len_str2)] | |
#init x | |
for i in range(len_str1): | |
matrix[i] = i | |
#init y | |
for j in range(0, len(matrix), len_str1): | |
if j % len_str1 == 0: | |
matrix[j] = j // len_str1 | |
for i in range(1, len_str1): | |
for j in range(1, len_str2): | |
if str1[i-1] == str2[j-1]: | |
cost = 0 | |
else: | |
cost = 1 | |
matrix[j*len_str1+i] = min(matrix[(j-1)*len_str1+i]+1, | |
matrix[j*len_str1+(i-1)]+1, | |
matrix[(j-1)*len_str1+(i-1)] + cost) | |
return matrix[-1] | |
def difflib_leven(str1, str2): | |
leven_cost = 0 | |
s = difflib.SequenceMatcher(None, str1, str2) | |
for tag, i1, i2, j1, j2 in s.get_opcodes(): | |
#print('{:7} a[{}: {}] --> b[{}: {}] {} --> {}'.format(tag, i1, i2, j1, j2, str1[i1: i2], str2[j1: j2])) | |
if tag == 'replace': | |
leven_cost += max(i2-i1, j2-j1) | |
elif tag == 'insert': | |
leven_cost += (j2-j1) | |
elif tag == 'delete': | |
leven_cost += (i2-i1) | |
return leven_cost | |
if __name__ == '__main__': | |
str1 = input('str1:') | |
str2 = input('str2:') | |
print('normal_leven: {}'.format(normal_leven(str1, str2))) | |
print('python_difflib_leven: {}'.format(difflib_leven(str1, str2))) | |
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