反转 get_matching_blocks 来自 python 2.7 中 difflib 的结果并获得不匹配的块

Question

下面python2.7的例子returns string1和string2的匹配块：

import difflib    

string1 = "This is a test"
string2 = "This ain't a testament"

s = difflib.SequenceMatcher(lambda x: x == " ", string1, string2)

for block in s.get_matching_blocks():
    a,b,size = block
    print "string1[%s] and string2[%s] match for %s characters" % block

以上程序的结果如下：

string1[0] and string2[0] match for 5 characters
string1[5] and string2[6] match for 1 characters
string1[7] and string2[10] match for 7 characters
string1[14] and string2[22] match for 0 characters

我想反转结果和 return string1 和 string2 的不匹配块，如下所示：

string1[6] mismatch for 1 characters

string2[5] mismatch for 1 characters
string2[7] mismatch for 3 characters
string2[17] mismatch for 5 characters

注意：两个字符串的匹配块总数相同，但不匹配的块会因字符串而异。

这里是字符串的颜色编码表示，其中黑色=匹配，红色=不匹配。

Answer 1

在我看来，应该可以遍历匹配的块来计算不匹配的部分。下面粘贴了一个快速解决方案（读作 "tested only with the input in the question"）。看看能不能帮你算出最终的解决方案。

注意：我现在只能使用 Python3 解释器，但由于这个问题不是 version-specific，所以我发布了这个解决方案。

import difflib

string1 = "This is a test"
string2 = "This ain't a testament"

s = difflib.SequenceMatcher(lambda x: x == " ", string1, string2)

s1_miss = list()
s2_miss = list()
s1_cur_off = 0
s2_cur_off = 0
for block in s.get_matching_blocks():
    a,b,size = block
    print("string1[%s] and string2[%s] match for %s characters" % block)
    if a > s1_cur_off:
        s1_miss.append((s1_cur_off, a-1, a-1-s1_cur_off + 1))
    s1_cur_off = a + size
    if b > s2_cur_off:
        s2_miss.append((s2_cur_off, b-1, b-1-s2_cur_off + 1))
    s2_cur_off = b + size
print(s1_miss)
print(s2_miss)

输出：为每个字符串转储不匹配列表。列表的每个元素都有three-tuples：不匹配的开始和结束偏移量和长度（主要用于调试）。

string1[0] and string2[0] match for 5 characters
string1[5] and string2[6] match for 1 characters
string1[7] and string2[10] match for 7 characters
string1[14] and string2[22] match for 0 characters
[(6, 6, 1)]
[(5, 5, 1), (7, 9, 3), (17, 21, 5)]

反转 get_matching_blocks 来自 python 2.7 中 difflib 的结果并获得不匹配的块

Invert get_matching_blocks results from difflib in python 2.7 and get MISMATCHED blocks

python

difflib

python-2.7