python创建和读取文件的一个小例子（摘自python核心编程）

#写入文件

import os

ls=os.linesep  #系统的换行符
while True:
    fname=raw_input("Please input file name ")
    if os.path.exists(fname):
        print "the file already exists"
    else:
        break
all=[]
print "\nEnter lines . to quit\n"

while True:
    entry=raw_input(">")
    if entry=='.':
        break
    else:
        all.append(entry)

#读取文件

fname=raw_input('Please enter the filename to read: ')
try:
    fobj=open(fname,'r')

except IOError,e:
        print "*** file open error: "+e
else:
    for eachLine in fobj:
        print eachLine,
    fobj.close()