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  • python 核心编程课后练习(chapter 3)

    3-8

     1 #3-8
     2 "makeTextFile.py -- create text file"
     3 
     4 import os
     5 ls = os.linesep
     6 
     7 #get filename
     8 fname = raw_input()
     9 while True:
    10 
    11   if os.path.exists(fname):
    12     print "ERROR: '%s' already exists" % fname
    13   else:
    14     break
    15 all = []
    16 print "
    Enter lines ('.' by itself to quit).
    "      
    17 
    18 while True:
    19   entry = raw_input('newline:')
    20   if entry == '.':
    21     break
    22   else:
    23     all.append(entry)
    24 
    25 fobj = open(fname, 'w')
    26 fobj.writelines(['%s%s' % (x, ls) for x in all])
    27 fobj.close()
    28 print "DONE!" 
    View Code

    3-10

     1 #3-10
     2 "readtextFile.py---read and display text"
     3 import os
     4 
     5 fname = raw_input("Enter file name:")
     6 print
     7 
     8 if os.path.exists(fname):
     9   fobj = open(fname, 'r')
    10   for eachline in fobj:
    11     print eachline.strip()
    12   fobj.close()
    13 else:
    14   print "file not exists!!"  
    15 
    16 #3-11
    17 "readtextFile.py---read and display text"
    18 
    19 fname = raw_input("Enter file name:")
    20 print
    21 
    22 try:
    23   fobj = open(fname, 'r')
    24 except IOError, e:
    25   print "*** file open error: ", e
    26 else:
    27   for eachline in fobj:
    28     print eachline.strip()
    29   fobj.close()  
    View Code

    3-12

     1 #3-12
     2 "readtextFile.py---read and display text"
     3 import os
     4 ls = os.linesep
     5 
     6 print """Enter your option:
     7 (w)create a file
     8 (r)read a file
     9 (others)exit
    10 """
    11 
    12 def WriteFile(str):
    13   all = []
    14   if os.path.exists(str):
    15     print "ERROR: '%s' already exists" % fname
    16     return
    17   
    18   print "
    Enter lines ('.' by itself to quit).
    "
    19   while True:
    20       entry = raw_input('newline:')
    21       if entry == '.':
    22         break
    23       else:
    24         all.append(entry)
    25 
    26     fobj = open(fname, 'w')
    27     fobj.writelines(['%s%s' % (x, ls) for x in all])
    28     fobj.close()
    29     print "DONE!" 
    30 
    31 def ReadFile(str):
    32   #fname = raw_input("Enter file name:")
    33   print
    34   
    35   if os.path.exists(str):
    36       fobj = open(str, 'r')
    37       for eachline in fobj:
    38         print eachline.strip()
    39       fobj.close()
    40   else:
    41       print "file not exists!!" 
    42     
    43   
    44 opt =raw_input("your option is:")
    45 
    46 if(opt == 'w'):
    47   fname = raw_input("the file to write is: ")
    48   WriteFile(fname)
    49 elif opt== 'r':
    50   fname = raw_input("the file to read is: ")   
    51   ReadFile(fname)
    52 else:
    53   print "exit" 
    View Code

    3-13

     1 #3-13
     2 "readtextFile.py---read and display text"
     3 import os
     4 ls = os.linesep
     5 
     6 print """Enter your option:
     7 (w)create a file
     8 (r)read a file
     9 (m)modify a file
    10 (others)exit
    11 """
    12 
    13 def WriteFile(str):
    14   all = []
    15   if os.path.exists(str):
    16     print "ERROR: '%s' already exists" % fname
    17     return
    18   
    19   print "
    Enter lines ('.' by itself to quit).
    "
    20   while True:
    21       entry = raw_input('newline:')
    22       if entry == '.':
    23         break
    24       else:
    25         all.append(entry)
    26 
    27     fobj = open(fname, 'w')
    28     fobj.writelines(['%s%s' % (x, ls) for x in all])
    29     fobj.close()
    30     print "DONE!" 
    31 
    32 def ReadFile(str):
    33   #fname = raw_input("Enter file name:")
    34   print
    35   
    36   if os.path.exists(str):
    37       fobj = open(str, 'r')
    38       for eachline in fobj:
    39         print eachline.strip()
    40       fobj.close()
    41   else:
    42       print "file not exists!!" 
    43 
    44 def ModifyFile(str):
    45   all = []
    46   if os.path.exists(str):
    47     i = 1
    48     fobj = open(str, 'r')
    49     for eachline in fobj:
    50       newline = eachline.strip()
    51       print "line %d: %s" % (i,newline)
    52       newline = raw_input("replace with:")    
    53       all.append(newline)
    54       i+=1
    55     fobj.close()
    56     
    57     opt = raw_input("do you want to save your changes,
    y(yes) 
    other(n):")
    58     if opt == 'y':    
    59       output = open(str, 'w')
    60       output.writelines(['%s%s' % (x, ls) for x in all])
    61       output.close()
    62     else:
    63       return  
    64   else:
    65     print "file not exists!!"       
    66   
    67 opt =raw_input("your option is:")
    68 
    69 if(opt == 'w'):
    70   fname = raw_input("the file to write is: ")
    71   WriteFile(fname)
    72 elif opt== 'r':
    73   fname = raw_input("the file to read is: ")   
    74   ReadFile(fname)
    75 elif opt == 'm':
    76   fname = raw_input("the file to modify is:")
    77   ModifyFile(fname)
    78   print "the new file content is:" 
    79   ReadFile(fname) 
    80 else:
    81   print "exit" 
    View Code
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  • 原文地址:https://www.cnblogs.com/huking/p/3231899.html
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