《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()