1. difflib模块简介

  • difflib为python的标准库模块,无需安装。
  • 作用是对比文本之间的差异。并且支持输出可读性比较强的HTML文档,与Linux下的diff命令相似。在版本控制方面非常有用。

2. difflib模块用法

用法说明
splitlines()按照行(’\r’, ‘\r\n’, \n’)分隔,返回一个包含各行作为元素的列表,如果参数 keepends 为 False,不包含换行符,如果为 True,则保留换行符。
difflib.Differ()用于过滤函数(或None),默认值是None
d.compare(a,b)比较两个行序列,并生成delta(一系列行)
difflib.HtmlDiff()可以用于创建一个完整HTML文件,该文件显示具有行间和行内更改突出的文本的逐行比较
d.make_file(text1,text2)比较a和b(字符串列表)并返回一个字符串,该字符串是一个完整的HTML文件,其中包含一个表格,显示逐行差异,突出显示行间和行内更改

3. 符号理解

符号含义
‘-’包含在第一个系列行中,但不包含第二个
‘+’包含在第二个系列行中,但不包含第一个
’ ’两个系列行一致
‘?’存在增量差异
‘^’存在差异字符

4. 实现文本对比

import difflib
text1 = '''  1. Beautiful is better than ugly.
       2. Explicit is better than implicit.
       3. Simple is better than complex.
       4. Complex is better than complicated.
		'''.splitlines(keepends=True)
text2 = '''  1. Beautiful is better than ugly.
       3.   Simple is better than complex.
       4. Complicated is better than complex.
       5. Flat is better than nested.
     '''.splitlines(keepends=True)

d = difflib.Differ()
print(''.join(list(d.compare(text1,text2))))

输出结果:

    1. Beautiful is better than ugly.
-        2. Explicit is better than implicit.
-        3. Simple is better than complex.
+        3.   Simple is better than complex.
?          ++
-        4. Complex is better than complicated.
?                 ^                     ---- ^
+        4. Complicated is better than complex.
?                ++++ ^                      ^
- 		+        5. Flat is better than nested.
+      

在这里插入图片描述
用html方式对比

import difflib
text1 = '''  1. Beautiful is better than ugly.
       2. Explicit is better than implicit.
       3. Simple is better than complex.
       4. Complex is better than complicated.
		'''.splitlines(keepends=True)
text2 = '''  1. Beautiful is better than ugly.
       3.   Simple is better than complex.
       4. Complicated is better than complex.
       5. Flat is better than nested.
     '''.splitlines(keepends=True)

d = difflib.HtmlDiff()
htmlContent = d.make_file(text1,text2)
# print(htmlContent)
with open('diff.html','w') as f:
    f.write(htmlContent)

输出结果:
在这里插入图片描述

5. linux文件之间的对比

import difflib
filename1 = '/tmp/passwd'
filename2 = '/tmp/passwd1'

with open(filename1) as f1,open(filename2) as f2:
    content1 = f1.read().splitlines(keepends=True)
    content2 = f2.read().splitlines(keepends=True)

d = difflib.HtmlDiff()
htmlcontent = d.make_file(content1,content2)
with open('passwdDiff.html','w') as f:
    f.write(htmlcontent)

输出结果:
在这里插入图片描述

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