子网掩码转换

# coding:utf-8
 
def exchange_mask(mask):
    """
    转换子网掩码格式
    """
    # 计算二进制字符串中 '1' 的个数
    count_bit = lambda bin_str: len([i for i in bin_str if i=='1'])
    # 分割字符串格式的子网掩码为四段列表
    mask_splited = mask.split('.')
    # 转换各段子网掩码为二进制, 计算十进制
    mask_count = [count_bit(bin(int(i))) for i in mask_splited]
    return sum(mask_count)
 
if __name__ == '__main__':
    print exchange_mask('255.255.0.0')

 

===================================================================

 

def exchange_maskint(mask_int):
  bin_arr = ['0' for i in range(32)]
  for i in range(mask_int):
    bin_arr[i] = '1'
  tmpmask = [''.join(bin_arr[i * 8:i * 8 + 8]) for i in range(4)]
  tmpmask = [str(int(tmpstr, 2)) for tmpstr in tmpmask]
  return '.'.join(tmpmask)
if __name__ == '__main__':
  print exchange_maskint(24)