python学习之——判断ip地址合法性

# -*- coding: cp936 -*-
def isIpaddr(addr):
    flag=0
    data=addr.split(".")
    if len(data)==4:
        for i in range(0,4):
            if 0<int(data[i])<255:
                 pass
            else:
                 flag=1
        if flag==0:
            print "%s is reasonable
" % addr
        else:
            print "%s is unreasonable,value is wrong
" % addr
    else:
         print "%s is unreasonable,length is wrong
" % addr
        

if __name__=='__main__':
    print '—'*20
    print "Tip:. means quit"
    print '—'*20
    while True:
        ipaddr=raw_input("please enter ipaddress:")
        if ipaddr!='.':
            isIpaddr(ipaddr)
        else:
            print 'quit'
            break