difflib 标准库详解：Python 文本对比的利器

difflib 是 Python 的标准库之一，它提供了很多用于计算和比较序列差异的功能。在这里，我们主要关注它在文本比较方面的应用。

1. 使用 difflib.Differ() 进行差异化比较

import difflib
 
text1 = """The Zen of Python, by Tim Peters
 
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
"""
text2 = """The Zen of Python, by Tim Peters
 
Beautiful is better than ugly.
Simple is better than complex.
"""
 
d = difflib.Differ()
diff = d.compare(text1.splitlines(), text2.splitlines())
 
print('\n'.join(diff))

2. 使用 difflib.HtmlDiff() 生成 HTML 格式的差异报告

import difflib
 
text1 = """The Zen of Python, by Tim Peters
 
Beautiful is better than ugly.
Explicit is better than implicit.
Simple is better than complex.
Complex is better than complicated.
"""
text2 = """The Zen of Python, by Tim Peters
 
Beautiful is better than ugly.
Simple is better than complex.
"""
 
d = difflib.HtmlDiff()
print(d.make_file(text1.splitlines(), text2.splitlines()))

3. 使用 difflib.SequenceMatcher() 进行复杂的序列比较

import difflib
 
text1 = "abcd"
text2 = "axcd"
 
s = difflib.SequenceMatcher(None, text1, text2)
 
for tag, i1, i2, j1, j2 in s.get_opcodes():
    print(f"{tag} {text1[i1:i2]} {text2[j1:j2]}")

difflib 提供了丰富的文本比较功能，可以方便地进行文件比较、多行字符串比较等。在实际应用中，可以根据需要选择合适的工具和方法。