How use netaddr to convert subnet mask to cidr in Python
Using netaddr:
>>> from netaddr import IPAddress>>> IPAddress('255.255.255.0').netmask_bits()24Using ipaddress from stdlib:
>>> from ipaddress import IPv4Network>>> IPv4Network('0.0.0.0/255.255.255.0').prefixlen24You can also do it without using any libraries: just count 1-bits in the binary representation of the netmask:
>>> netmask = '255.255.255.0'>>> sum(bin(int(x)).count('1') for x in netmask.split('.'))24
Use the following function. it is fast, reliable, and don't use any library.
# code to convert netmask ip to cidr numberdef netmask_to_cidr(netmask): ''' :param netmask: netmask ip addr (eg: 255.255.255.0) :return: equivalent cidr number to given netmask ip (eg: 24) ''' return sum([bin(int(x)).count('1') for x in netmask.split('.')])