CODEWITHSUNDEEP
pythonsortingip-address
Charlweed
Charlweed

Reputation: 1614

How can I enhance this python code to do a natural sort of a list of FQN hostnames and ip addresses?

Say I have

apple.berry.cherry.za
100.100.100.100
100.100.100.20
apple.berry.banna.au

and I want

100.100.100.20
100.100.100.100
apple.berry.cherry.au
apple.berry.banna.za

I have the following python code which sorts FQN hostnames the way I want, but it only does alpha-numeric sorting on IP addresses:

#!/bin/python
from fileinput import input
for y in sorted([x.strip().split('.')[::-1] for x in input()]): print '.'.join(y[::-1])

I can add a function to convert a triplet to an integer:

def atoi(text):
    return int(text) if text.isdigit() else text

But because I don't know python, I don't know how to call atoi() on each element of the list before it is sorted. How to do?

Upvotes: 1

Views: 127

Answers (2)

kszl
kszl

Reputation: 1213

You can apply a function to each element of the list by using map filter. So it'd be:

for y in sorted([map(atoi, x.strip().split('.')[::-1]) for x in input()]):
    print '.'.join(y[::-1])

Edit: As pointed by @Slam, if you decide to use Python 3 one day, translating the foregoing code won't be straightforward. It doesn't allow you to compare ints and strings.

Upvotes: 1

Slam
Slam

Reputation: 8572

If you expect ipv4 only and this is on-time utility script, you can try dirty hack like

sorted(lst, key=lambda x: [i.zfill(3) if i.isdigit() else i for i in x.split('.')][::-1])

If not, you probably wont end up with one-liner. You need natural sorting for digits, which is not available out of the box

Upvotes: 0

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