字符串编辑距离算法的python实现

理解：将字符串A编辑为字符串B所进行的最小操作数，操作包括插入、删除、修改。

举例1：“kitten"变为"sitting”
‘k’->‘s’
‘e’变为’i’
‘kitten’末尾还需加上’g’
故字符串编辑距离为3

举例2：“fish abc"变为"pushabdc”
‘f’ -> ‘p’
‘i’ -> ‘u’
’ '删除
‘abc’中’c’前增加’d’
故字符串编辑距离为4

参考C++代码修改

import numpy as np

def Edit_Distance(word_a,word_b):
	len_a = len(word_a)
    len_b = len(word_b)  
    dp = np.zeros(1010,dtype = int)
    for j in range(1,len_b+1):
    	dp[j] = j
    for i in range(1,len_a+1):
    	t1 = dp[0]
        dp[0] = dp[0] + 1
        for j in range(1,len_b+1):
        	t2 = dp[j]
            if word_a[i-1] == word_b[j-1]:
            	dp[j] = t1
            else:
            	dp[j] =  min(t1, dp[j-1], dp[j]) + 1
            t1 = t2
	print(dp[len_b])
	return dp[len_b]    

Edit_Distance('fish abc','pushabdc')

# 输出：
# 4