文件内容差异对比方法

一、两个字符串的对比

1、两个字符串的对比输出

#!/bin/env python

import difflib

text1 = """text1:

This module provides classes and functions for comparing sequences v7.5"""

text1_lines = text1.splitlines()

text2 = """text2:

This module provides classes and functions for comparing sequences v7.4"""

text2_lines = text2.splitlines()

d = difflib.Differ()

diff = d.compare(text1_lines,text2_lines)

print ‘\n‘.join(list(diff))

本示例采用Differ()类对两个字符串进行比较，另外difflib的sequenceMatcher()类支持任意类型序列的比较，HtmlDiff()类支持将比较结果输出为HTML格式，示例运行结果如图2-1所示

2、生成美观的对比HTML格式文档

采用HtmlDiff()类的make_file()方法就可以生成美观的HTML文档，对示例1中代码按以下进行修改：

d = difflib.Differ()

diff = d.compare(text1_lines,text2_lines)

print ‘\n‘.join(list(diff))

替换成：

d = difflib.HtmlDiff()

print d.make_file(text1_lines,text2_lines)

将新文件命名为diff2.py。运行#python diff2.py,再使用浏览器打开diff.html文件，结果如果2-2所示，HTML文档包括了行号、差异标志、图例等信息，可读性增强了许多。

二、两个文件的对比

shell # vi diff3.py

#!/bin/env python

import difflib

import sys

try:

textfile1=sys.argv[1]

textfile2=sys.argv[2]

except Exception,e:

print "Error:"+str(e)

print "Usage: diff2.py filename1 filename2"

sys.exit()

def readfile(filename):

try:

fileHandle = open(filename, ‘rb‘)

text = fileHandle.read().splitlines()

fileHandle.close()

return text

except IOError as error:

print (‘Read file Error:‘+str(error))

sys.exit()

if textfile1=="" or textfile2=="":

print "Usage:diff3.py filename1 finename2"

sys.exit()

text1_lines = readfile(textfile1)

text2_lines = readfile(textfile2)

d = difflib.HtmlDiff()

print d.make_file(text1_lines,text2_lines)

从图2-3中可以看出diff.py和diff2.py的差别