项目中有这样的需求，通过IP地址判断客户端是网通的还是电信的。从同事那拿了个纯文本的IP纯真数据库，用Python写了一个小程序，感觉挺好的。下面给出实现源码：
#!/usr/bin/env python
# -*- coding: utf-8 -*-
from bisect import bisect
_LIST1, _LIST2 = [], []
_INIT = False
ip2int = lambda ip_str: reduce(lambda a, b: (a << 8) + b, [int(i) for i in ip_str.split('.')])
def _init():
global _LIST, _INIT
if not _INIT:
for l in open('ipdata.txt', 'rb'):
ip1, ip2 = l.split()[:2]
addr = ' '.join(l.split()[2:])
ip1, ip2 = ip2int(ip1), ip2int(ip2)
_LIST1.append(ip1)
_LIST2.append((ip1, ip2, addr))
_INIT = True
def ip_from(ip):
_init()
i = ip2int(ip)
idx = bisect(_LIST1, i)
assert(idx > 0)
if len(_LIST1) <= idx:
return u'unknown ip address %s' % ip
else:
frm, to ,addr = _LIST2[idx - 1]
if frm <= i <= to:
return addr
else:
return u'unknown ip address %s' % ip
if __name__ == '__main__':
print ip_from('115.238.54.106')
print ip_from('220.181.29.160')
print ip_from('115.238.54.107')
print ip_from('8.8.8.8')
