python - 如何将 python 的 difflib.unified_diff 的输出应用于原始字符串？

Question

因此，使用 Python 的 difflib ，我可以生成两个字符串的差异:

foo = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit.\n Nullam sed orci lobortis lectus bibendum vehicula.\n Integer iaculis eros porttitor velit porttitor scelerisque.\n Nunc venenatis nibh.'.splitlines()
bar = 'Lorem ipsum dolor sit amet, consectetur adipiscing elit.\n Mauris placerat, odio ut viverra gravida, elit leo tincidunt nisi, a pellentesque velit arcu id magna.\n Integer iaculis eros porttitor velit porttitor scelerisque.\n Nunc venenatis nibh.'.splitlines()

diff = difflib.unified_diff(foo, bar, lineterm='')

如果需要，我们可以检查差异:

>>> print '\n'.join(diff)
--- 
+++ 
@@ -1,4 +1,4 @@
 Lorem ipsum dolor sit amet, consectetur adipiscing elit.
- Nullam sed orci lobortis lectus bibendum vehicula.
+ Mauris placerat, odio ut viverra gravida, elit leo tincidunt nisi, a pellentesque velit arcu id magna.
  Integer iaculis eros porttitor velit porttitor scelerisque.
  Nunc venenatis nibh.

这就是我被困的地方。我如何将该差异应用于字符串 foo 以生成字符串 bar？

Answer 1

如果你使用 ndiff 那么你可以使用 restore 恢复原始字符串

>>> diff = difflib.ndiff(foo, bar)
>>> diff = list(diff)
>>> print ''.join(difflib.restore(diff, 2))
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sed orci lobortis lectus bibendum baculo mihi. Integer iaculis eros porttitor velit porttitor scelerisque. Nunc venenatis nibh.
>>> ''.join(difflib.restore(diff, 2))==''.join(bar)
True
>>> ''.join(difflib.restore(diff, 1))==''.join(foo)
True
>>> 

请注意，由于统一差异通常会删除比较等于开头的行，因此几乎不可能恢复到原始字符串。 ndiff 显示了所有内容，因此可以直接恢复原始内容。