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 "\nEnter lines ('.' by itself to quit).\n"      

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!" 

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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()  

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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 "\nEnter lines ('.' by itself to quit).\n"

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" 

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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 "\nEnter lines ('.' by itself to quit).\n"

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,\ny(yes) \nother(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" 

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