Merge/Join two Dataframes, one with IP addresses, one with IP Networks

Question

I have two dataframes, one containing IP addresses (df_ip), one containing IP networks (df_network).
The IP's and Networks are of the type ipaddress.ip_address and ipaddress.ip_network, which enables checking if an IP lies in the Network (ip in network).

The dataframes look as follows:

df_ip:
    IP
0   10.10.10.10
1   10.10.20.10
2   10.10.20.20

df_network:
    NETWORK         NETWORK_NAME
0   10.10.10.0/28   Subnet1
1   10.10.20.0/27   Subnet2

I want to merge/join df_ip with df_network, adding the name of the network in which the IP lies per row.
For this small instance, it should return the following:

df_merged:
    IP            NETWORK_NAME
0   10.10.10.10   Subnet1
1   10.10.20.10   Subnet2
2   10.10.20.20   Subnet2

My actual dataframes are much larger, so id prefer to not use for-loops to maintain efficiency.
How can I best achieve this? If this requires changing the datatypes, that's okay.

Note: I've added code below to create the data for convenience.

import pandas as pd
import ipaddress

# Create small IP DataFrame
values_ip = [ipaddress.ip_address('10.10.10.10'),
             ipaddress.ip_address('10.10.20.10'),
             ipaddress.ip_address('10.10.20.20')]

df_ip = pd.DataFrame()
df_ip['IP'] = values_ip

# Create small Network DataFrame
values_network = [ipaddress.ip_network('10.10.10.0/28'),
                  ipaddress.ip_network('10.10.20.0/27')]
names_network = ['Subnet1',
                 'Subnet2']

df_network = pd.DataFrame()
df_network['NETWORK'] = values_network
df_network['NETWORK_NAME'] = names_network

user_12207320 · Answer

an efficient way to avoid any loops is to use numpy arrays to check where ip & netmask == network_address, which is how to check whether an ip lies within the network.

note that this returns only the first matching network name

import numpy as np
net_masks = df_network.NETWORK.apply(lambda x: int(x.netmask)).to_numpy()
network_addresses = df_network.NETWORK.apply(lambda x: int(x.network_address)).to_numpy()

def get_first_network(ip):
    is_in_network = int(ip) & net_masks == network_addresses
    indices = np.argwhere(is_in_network)
    if indices.size>0:
        return df_network.loc[int(indices[0]), 'NETWORK_NAME' ]
    else:
        None

df_ip['network_name'] = df_ip.IP.apply(get_first_network)

which results in:

            IP network_name
0  10.10.10.10      Subnet1
1  10.10.20.10      Subnet2
2  10.10.20.20      Subnet2

Merge/Join two Dataframes, one with IP addresses, one with IP Networks

1 Answers