《python核心编程》笔记——文件的创建、读取和显示

创建文件（makeTextFile.py）脚本提醒用户输入一个尚不存在的文件名，然后由用户输入文件每一行，最后将所有文本写入文本文件

 #!/usr/bin/env python

 'makeTextFile.py -- creat text file'

 import os
 ls = os.linesep

 # get file name
 while True:
 if os.path.exists(fname):          #不存在返False，存在返True
      print "ERROR: '%s' already exists" % fname
 else:
       break

 #get file content (text) lines
 all = []
 print "\nEnter lines ('.' by itself to quit).\n"

 #loop until user terminates input
 while True:
      entry = raw_input('>')
      if entry == '.':
           break
      else:
           all.append(entry)

 #write lines to file with proper line-ending
 fobj = open(fname, 'w')
 fobj.writelines(['%s%s' % (x,ls) for x in all])
 #列表解析，将列表中每行（每个元素）都写入文件，两个%s分别是字符串和每行结束符
 fobj.close
 print 'DONE!'

文件读取和显示(readTextFile.py)

 #!/user/bin/env python

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

 # get filename
 fname = raw_input('Enter filename')
 print          #隔开提示和文本
 # attempt to open file for reading
 try:
      fobj = open(fname, 'r')
 except IOError, e:
      print "*** file open error:",e
 else:
      # dispaly content to the screen
      for eachLine in fobj
           print eachLine,
      fobj.close()