Python中fileinput模塊使用

fileinput模塊可以對一個或多個文件中的內容進行迭代、遍歷等操作。該模塊的input()函數有點類似文件

readlines()方法，區別在於前者是一個迭代對象，需要用for循環迭代，后者是一次性讀取所有行。

用fileinput對文件進行循環遍歷，格式化輸出，查找、替換等操作，非常方便。

【典型用法】

import fileinput
for line in fileinput.input():
    process(line)

【基本格式】

fileinput.input([files[, inplace[, backup[, bufsize[, mode[, openhook]]]]]])

 

【默認格式】

fileinput.input (files=None, inplace=False, backup='', bufsize=0, mode='r', openhook=None)

files:                  #文件的路徑列表，默認是stdin方式，多文件[ '1.txt' , '2.txt' ,...]

inplace:                #是否將標准輸出的結果寫回文件，默認不取代

backup:                 #備份文件的擴展名，只指定擴展名，如.bak。如果該文件的備份文件已存在，則會自動覆蓋。

bufsize:                #緩沖區大小，默認為 0 ，如果文件很大，可以修改此參數，一般默認即可

mode:                   #讀寫模式，默認為只讀

openhook:               #該鈎子用於控制打開的所有文件，比如說編碼方式等;

 

【常用函數】

 

fileinput.input()       #返回能夠用於for循環遍歷的對象
fileinput.filename()    #返回當前文件的名稱
fileinput.lineno()      #返回當前已經讀取的行的數量（或者序號）
fileinput.filelineno()  #返回當前讀取的行的行號
fileinput.isfirstline() #檢查當前行是否是文件的第一行
fileinput.isstdin()     #判斷最后一行是否從stdin中讀取
fileinput.close()       #關閉隊列

【常見例子】

例子01: 利用fileinput讀取一個文件所有行

>>> import fileinput
>>> for line in fileinput.input('data.txt'):
    print line,
#輸出結果
Python
Java 
C/C++
Shell

命令行方式:

#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對多文件操作，並原地修改內容

#test.py
#---樣本文件---
c:Python27>type 1.txt
first
second
 
c:Python27>type 2.txt
third
fourth
#---樣本文件---
import fileinput
 
def process(line):
    return line.rstrip() + ' line'
 
for line in fileinput.input(['1.txt','2.txt'],inplace=1):
    print process(line)
 
#---結果輸出---
c:Python27>type 1.txt
first line
second line
 
c:Python27>type 2.txt
third line
fourth line

命令行方式:

#test.py
import fileinput
 
def process(line):
    return line.rstrip() + ' line'
 
for line in fileinput.input(inplace = True):
    print process(line)
 
#執行命令
c:Python27>python test.py 1.txt 2.txt

例子03: 利用fileinput實現文件內容替換，並將原文件作備份

#樣本文件:
#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'),
     
#最后結果:
#data.txt
Python
Java
C/C++
Shell
#並生成:
#data.txt.bak文件

例子04: 利用fileinput將CRLF文件轉為LF

import fileinput
import sys
 
for line in fileinput.input(inplace=True):
    #將Windows/DOS格式下的文本文件轉為Linux的文件
    if line[-2:] == 
:  
        line = line + 
 
    sys.stdout.write(line)

例子05: 利用fileinput對文件簡單處理

#FileName: test.py
import sys
import fileinput
 
for line in fileinput.input(r'C:Python27info.txt'):
    sys.stdout.write('=> ')
    sys.stdout.write(line)
 
#輸出結果   
>>> 
=> 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批處理文件

#---測試文件: test.txt test1.txt test2.txt test3.txt---
#---腳本文件: 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(),
     
     
#---輸出結果:
>>> 
-------------------- 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

#--樣本文件--
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
 
#---測試腳本---
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)
 
#---測試結果---
=> 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: 提取符合條件的電話號碼

#---樣本文件: phone.txt---
010-110-12345
800-333-1234
010-99999999
05718888888
021-88888888
 
#---測試腳本: test.py---
import re
import fileinput
 
pattern = '[010|021]-d{8}'  #提取區號為010或021電話號碼，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,
 
#---輸出結果:---
>>> 
==================================================
Filename:phone.txt | Line Number:3 | 010-99999999
==================================================
Filename:phone.txt | Line Number:5 | 021-88888888
>>>
 

例子09:利用fileinput實現類似於grep的功能

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.* fileinput *.py

例子10:利用fileinput做正則替換

#---測試樣本: input.txt
* [Learning Python](#author:Mark Lutz)
     
#---測試腳本: test.py
import fileinput
import re
  
for line in fileinput.input():
    line = re.sub(r'* [(.*)](#(.*))', r'