Write a python program to find the editing distance [python] [Levenshtein distance]

Editing distance is what

--Indicator to compare two strings ――How many times can you convert from s1 to s2 by performing the following three operations? --Replace --Insert

Rough explanation

--Consider converting a string from s1 to s2

s1 = "aaa"
s2 = "aab"

--If the character string is as above, the edit distance is 1. --One replacement

s1 = "aba"
s2 = "cc"

--If the character string is as above, the edit distance is 3 --Replacement twice --One insertion


There is a very useful python module python-Levenshtein The official documentation is here


Install with pip

$ pip install python-Levenshtein



import Levenshtein
import sys

args = sys.argv

with open(args[1], "r") as f_ans:
    with open(args[2], "r") as f_ref:
        s_ans = f_ans.read()
        s_ref = f_ref.read()

print(Levenshtein.distance(s_ans, s_ref))

It's a simple program that just spits out the edit distance by specifying two text files as command line arguments.


Prepare two text files.


Helllo worb!!


Hello world!

To convert from tmp1.txt to tmp2.txt,

--Deleted one "l" from "Helllo" --About "worb" --Added "l" --Replace "b" with "d" -Delete one "!"

So the edit distance should be 4.

$ python leven.py tmp1.txt tmp2.txt

became. happy.


This is an article written by a person who tried to implement it by dynamic programming, but found that the module was missing and it became troublesome to implement. If you have any questions, please leave them in the comments.

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