項目中有這樣的需求，通過IP地址判斷客戶端是網通的還是電信的。從同事那拿了個純文本的IP純真數據庫，用Python寫了一個小程序，感覺挺好的。下面給出實現源碼：

#!/usr/bin/env python# -*- coding: utf-8 -*-from bisect import bisect_LIST1, _LIST2 = [], []_INIT = Falseip2int = 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')