以下3步问正确的程序片段：

1.写文件

#! /usr/bin/python3


‘makeTextFile.py -- create text file‘


import os


def write_file():
    "used to write a text file."
    
    ls = os.linesep
    #get filename
    fname = input("Please input filename:")


    while True:
    
        if os.path.exists(fname):
            print("Error: ‘%s‘ already exists" % fname)
            fname = input("Please input filename:")
        else:
            break
        
    #get file conent linesOnScreen
    all = []
    print("\nEnter lines (‘.‘ to quit).\n")


    while True:
        entry = input(‘>‘)
        if entry == ‘.‘:
            break
        else:
            all.append(entry)
            
    try:
        fobj = open(fname,  ‘w‘)
    except IOError as err:
        print(‘file open error: {0}‘.format(err))  
        
    fobj.writelines([‘%s%s‘ % (x,  ls) for x in all])
    fobj.close()
    
    print(‘WRITE FILE DONE!‘)
    
    return fname

2.读文档

#! /usr/bin/python3


‘readTextFile.py -- read and display text file.‘


def read_file(filename):
    ‘used to read a text file.‘
    
    try:
        fobj = open(filename,  ‘r‘)
    except IOError as err:
        print(‘file open error: {0}‘.format(err))  
    else:
        for eachLine in fobj:
            print(eachLine)
        fobj.close()
        

3.主程序

#! /usr/bin/python3


‘write_and_read_file.py -- write and read text file.‘


import makeTextFile
import readTextFile


if __name__ == ‘__main__‘:
    
    #wrie file
    filename = makeTextFile.write_file()
    
    #read file
    readTextFile.read_file(filename)

 一下为笔者自己所写：

1.写文档

#! /usr/bin/Python2.7

‘makeTextFile2--create text file‘

import os

def write_file():

   ls = os.linesep

   #get file[A1] 

   fileName = raw_input(‘plz input filename:‘)

   while True:

       if os.path.exists(fileName)     

           print(‘file already exists!‘)

                            [A2] 

       else:

           fileName = raw_input(‘plz input filename[A3] :‘)

   #get content in line

   all = []

   print(‘\nEnter line(‘.‘ to quit).\n‘)

   while True:

       entry = input[A4] (‘>‘)

                   [A5] 

       else:

            break[A6] 

       entry.append(all[A7] )

   fobj = open(fileName, ‘w[A8] ‘)

   fileName.writelines(‘%s%s‘ %(x, ls) for x in all[A9] )

fobj.close[A10] [A11] ()

2.读文档 

#! /usr/bin/Python2.7

‘readTextFile2--read text file‘

import os

def read_file[A12] ():

   try:

       fobj = open(fileName, ‘r‘)

   except IOError as err:

       print (‘read file error:{0}‘.format(err))

   else:

       for eachLine in fobj:

           print(eachLine)

       fobj.close()

 3.主函数

#! /usr/bin/Python2.7

‘main2—main function’

import makeTextFile.py[A13] 

import readTextFile.py

 [A14] 

fileName = makeTextFile.write_file()