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fileinput模块可以对一个或多个文件中的内容进行迭代、遍历等操作。该模块的input()函数有点类似文件readlines()方法，区别在于:前者是一个迭代对象，即每次只生成一行，需要用for循环迭代。后者是一次性读取所有行。在碰到大文件的读取时，前者无疑效率更高效。用fileinput对文件进行循环遍历，格式化输出，查找、替换等操作，非常方便。【典型用法】 代码如下:import fileinputfor line in fileinput.input(): process(line)【基本格式】 代码如下:fileinput.input([files[, inplace[, backup[, bufsize[, mode[, openhook]]]]]])【默认格式】 代码如下:fileinput.input (files=None, inplace=False, backup='', bufsize=0, mode='r', openhook=None)files: #文件的路径列表，默认是stdin方式，多文件['1.txt','2.txt',...] inplace: #是否将标准输出的结果写回文件，默认不取代 backup: #备份文件的扩展名，只指定扩展名，如.bak。如果该文件的备份文件已存在，则会自动覆盖。 bufsize: #缓冲区大小，默认为0，如果文件很大，可以修改此参数，一般默认即可 mode: #读写模式，默认为只读 openhook: #该钩子用于控制打开的所有文件，比如说编码方式等; 【常用函数】 代码如下:fileinput.input() #返回能够用于for循环遍历的对象 fileinput.filename() #返回当前文件的名称 fileinput.lineno() #返回当前已经读取的行的数量（或者序号） fileinput.filelineno() #返回当前读取的行的行号 fileinput.isfirstline() #检查当前行是否是文件的第一行 fileinput.isstdin() #判断最后一行是否从stdin中读取 fileinput.close() #关闭队列 【常见例子】例子01: 利用fileinput读取一个文件所有行 代码如下:>>> import fileinput >>> for line in fileinput.input('data.txt'): print line, #输出结果 Python Java C/C++ Shell 命令行方式: 代码如下:#test.py import fileinput for line in fileinput.input(): print fileinput.filename(),'|','Line Number:',fileinput.lineno(),'|: ',line c:>python test.py data.txt data.txt | Line Number: 1 |: Python data.txt | Line Number: 2 |: Java data.txt | Line Number: 3 |: C/C++ data.txt | Line Number: 4 |: Shell 例子02: 利用fileinput对多文件操作，并原地修改内容 代码如下:#test.py #---样本文件--- c:\Python27>type 1.txt first second c:\Python27>type 2.txt third fourth #---样本文件--- import fileinput def process(line): return line.rstrip() + ' line' for line in fileinput.input(['1.txt','2.txt'],inplace=1): print process(line) #---结果输出--- c:\Python27>type 1.txt first line second line c:\Python27>type 2.txt third line fourth line #---结果输出--- 命令行方式: 代码如下:#test.py import fileinput def process(line): return line.rstrip() + ' line' for line in fileinput.input(inplace = True): print process(line) #执行命令 c:\Python27>python test.py 1.txt 2.txt 例子03: 利用fileinput实现文件内容替换，并将原文件作备份 代码如下:#样本文件: #data.txt Python Java C/C++ Shell #FileName: test.py import fileinput for line in fileinput.input('data.txt',backup='.bak',inplace=1): print line.rstrip().replace('Python','Perl') #或者print line.replace('Python','Perl'), #最后结果: #data.txt Python Java C/C++ Shell #并生成: #data.txt.bak文件 代码如下:#其效果等同于下面的方式 import fileinput for line in fileinput.input(): print 'Tag:',line, #---测试结果: d:\>python Learn.py data_out.txt 例子04: 利用fileinput将CRLF文件转为LF 代码如下:import fileinput import sys for line in fileinput.input(inplace=True): #将Windows/DOS格式下的文本文件转为Linux的文件 if line[-2:] == "\r\n": line = line + "\n" sys.stdout.write(line) 例子05: 利用fileinput对文件简单处理 代码如下:#FileName: test.py import sys import fileinput for line in fileinput.input(r'C:\Python27\info.txt'): sys.stdout.write('=> ') sys.stdout.write(line) #输出结果 >>> => 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. => Flat is better than nested. => Sparse is better than dense. => Readability counts. => Special cases aren't special enough to break the rules. => Although practicality beats purity. => Errors should never pass silently. => Unless explicitly silenced. => In the face of ambiguity, refuse the temptation to guess. => There should be one-- and preferably only one --obvious way to do it. => Although that way may not be obvious at first unless you're Dutch. => Now is better than never. => Although never is often better than *right* now. => If the implementation is hard to explain, it's a bad idea. => If the implementation is easy to explain, it may be a good idea. => Namespaces are one honking great idea -- let's do more of those! 例子06: 利用fileinput批处理文件 代码如下:#---测试文件: test.txt test1.txt test2.txt test3.txt--- #---脚本文件: test.py--- import fileinput import glob for line in fileinput.input(glob.glob("test*.txt")): if fileinput.isfirstline(): print '-'*20, 'Reading %s...' % fileinput.filename(), '-'*20 print str(fileinput.lineno()) + ': ' + line.upper(), #---输出结果: >>> -------------------- Reading test.txt... -------------------- 1: AAAAA 2: BBBBB 3: CCCCC 4: DDDDD 5: FFFFF -------------------- Reading test1.txt... -------------------- 6: FIRST LINE 7: SECOND LINE -------------------- Reading test2.txt... -------------------- 8: THIRD LINE 9: FOURTH LINE -------------------- Reading test3.txt... -------------------- 10: THIS IS LINE 1 11: THIS IS LINE 2 12: THIS IS LINE 3 13: THIS IS LINE 4 例子07: 利用fileinput及re做日志分析: 提取所有含日期的行 代码如下:#--样本文件-- aaa 1970-01-01 13:45:30 Error: **** Due to System Disk spacke not enough... bbb 1970-01-02 10:20:30 Error: **** Due to System Out of Memory... ccc #---测试脚本--- import re import fileinput import sys pattern = '\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}' for line in fileinput.input('error.log',backup='.bak',inplace=1): if re.search(pattern,line): sys.stdout.write("=> ") sys.stdout.write(line) #---测试结果--- => 1970-01-01 13:45:30 Error: **** Due to System Disk spacke not enough... => 1970-01-02 10:20:30 Error: **** Due to System Out of Memory... 例子08: 利用fileinput及re做分析: 提取符合条件的电话号码 代码如下:#---样本文件: phone.txt--- 010-110-12345 800-333-1234 010-99999999 05718888888 021-88888888 #---测试脚本: test.py--- import re import fileinput pattern = '[010|021]-\d{8}' #提取区号为010或021电话号码，格式:010-12345678 for line in fileinput.input('phone.txt'): if re.search(pattern,line): print '=' * 50 print 'Filename:'+ fileinput.filename()+' | Line Number:'+str(fileinput.lineno())+' | '+line, #---输出结果:--- >>> ================================================== Filename:phone.txt | Line Number:3 | 010-99999999 ================================================== Filename:phone.txt | Line Number:5 | 021-88888888 >>> 例子09: 利用fileinput实现类似于grep的功能 代码如下:import sys import re import fileinput pattern= re.compile(sys.argv[1]) for line in fileinput.input(sys.argv[2]): if pattern.match(line): print fileinput.filename(), fileinput.filelineno(), line $ ./test.py import.*re *.py #查找所有py文件中，含import re字样的 addressBook.py 2 import re addressBook1.py 10 import re addressBook2.py 18 import re test.py 238 import re 例子10: 利用fileinput做正则替换 代码如下:#---测试样本: input.txt * [Learning Python](#author:Mark Lutz) #---测试脚本: test.py import fileinput import re for line in fileinput.input(): line = re.sub(r'\* (.∗)#(.*)', r'\1', line.rstrip()) print(line) #---输出结果: c:\Python27>python test.py input.txt Learning Python 例子11: 利用fileinput做正则替换，不同字模块之间的替换 代码如下:#---测试样本:test.txt [@!$First]&[*%-Second]&[Third] #---测试脚本:test.py import re import fileinput regex = re.compile(r'^([^&]*)(&)([^&]*)(&)([^&]*)') #整行以&分割，要实现[@!$First]与[*%-Second]互换 for line in fileinput.input('test.txt',inplace=1,backup='.bak'): print regex.sub(r'\3\2\1\4\5',line), #---输出结果: [*%-Second]&[@!$First]&[Third] 例子12: 利用fileinput根据argv命令行输入做替换 代码如下:#---样本数据: host.txt # localhost is used to configure the loopback interface # when the system is booting. Do not change this entry. 127.0.0.1 localhost 192.168.100.2 www.test2.com 192.168.100.3 www.test3.com 192.168.100.4 www.test4.com #---测试脚本: test.py import sys import fileinput source = sys.argv[1] target = sys.argv[2] files = sys.argv[3:] for line in fileinput.input(files,backup='.bak',openhook=fileinput.hook_encoded("gb2312")): #对打开的文件执行中文字符集编码 line = line.rstrip().replace(source,target) print line #---输出结果: c:\>python test.py 192.168.100 127.0.0 host.txt #将host文件中，所有192.168.100转换为:127.0.0 127.0.0.1 localhost 127.0.0.2 www.test2.com 127.0.0.3 www.test3.com 127.0.0.4 www.test4.com 09-15 03:24