【随手写程序】之phython 入门 读写文件程序

学习教程python核心编程第二版

 

课后练习之改写读写程序

 

import os
#line breaks  is Common Var
ls=os.linesep

#define writing  function
def writefile():
    while True:
        filename=raw_input("enter filename>")
        if(os.path.exists(filename)):
           print "%s,this file name is exists"
        else:
           break
           
    all=[]
    print "\n enter lines('.' by itself to quit).\n"
    while True:
        entry=raw_input('>')
        if entry=='.':
            break
        else:
            all.append(entry)
    fobj=open(filename,'w')
    fobj.writelines('%s%s'%(x,ls) for x in all)
    fobj.close()
    print 'done!'

#define reading  function
def readfile():
    while True:
        filename=raw_input('enter a exist filename:')
        if os.path.exists(filename):
            print 'file exist'
            break
        else:
            print 'file is no exist'
    try:
        fobj=open(filename,'r')
        for  eachline in fobj:
            print  eachline
        fobj.close()
    except  IOError,e:
        print 'file open error%s',e
    wait=raw_input('wait')
    


#program start
print'''enter operation method :
                          1.\'n\' or \'N\' is represent new  file
                          2.\'o\' OR \'O\' is represent open file'''
while True:
    operStr=raw_input('enter oper>')
    if(operStr=='o' or operStr=='O'):
         readfile()
         break
    elif(operStr=='n' or 'N'==operStr):
        writefile()
        break
    else:
        print 'pelase input operation method'