bytes clear solution for IP Network: Route Summarization by gyahun_dash - python coding challenges

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bytes solution in Clear category for IP Network: Route Summarization by gyahun_dash

def checkio(adds):
    version, length = [b * len(adds[0].split('.')) for b in (1, 8)]

    ints = [int.from_bytes(bytes(map(int, a.split('.'))), 'big') for a in adds]
    rembit = (max(ints) ^ min(ints)).bit_length()
    subnet = length - rembit

    prefix = ints[0] >> rembit << rembit
    address = '.'.join(map(str, map(int, prefix.to_bytes(version, 'big'))))

    return '{}/{}'.format(address, subnet)

March 11, 2016

Comments:

veky on March 13, 2016, 8:20 a.m.
LOL @ line 2. :-) And line 8 is a nice trick, but probably <pre class='brush: python'>ints[0] & ~0 << rembit </pre> would be easier to grok. But seriously... noone but me solved this with Python's library batteries for working with IP? Really sad. :-/

gyahun_dash on March 13, 2016, 11:39 a.m.
<blockquote> LOL @ line 2. :-) </blockquote> Thank you. It can treat IPv6 that is never appeared. <pre class='brush: python'>ints[0] & ~0 << rembit </pre> I like the following better to clear the order of calculations: <pre class='brush: python'>ints[0] & (~0 << rembit) </pre> <blockquote> But seriously… noone but me solved this with Python’s library batteries for working with IP? Really sad. :-/ </blockquote> I didn't think it can be used... <a href="https://www.checkio.org/wiki/Modules/SupportedModulesForPython3/">https://www.checkio.org/wiki/Modules/SupportedModulesForPython3/</a>

veky on March 14, 2016, 5:47 a.m.
<blockquote> IPv6 </blockquote> Yes, I know, that's why I laugh. :-) However, the analogy is not really viable, I'm sure you see it too. <blockquote> the order of calculations </blockquote> Well, the precedence is what it is precisely to be unsurprising and easy to write things like that. You usually and with a shift, not shift an and. :-) Imagine if someone wanted to write `a + (b * c)` with an excuse like yours. You'd be horrified, right? :-) Parentheses add visual noise to a line, and they shouldn't be used without good reason. (Function call is a good reason, unlike in Ruby.:) Luckily, & is commutative. <pre class='brush: python'>~0 << rembit & ints[0] </pre> maybe reads better. Luckily2, PEP8 and Guido agree (despite what many people think) that you _don't leave space always around operators, but its intention is precisely to indicate grouping. So <pre class='brush: python'>ints[0] & ~0<<rembit I guess it's the best. > think it can be used </pre> So just use it. meta-EAFP! :-D

gyahun_dash on March 23, 2016, 3:41 p.m.
I tried it(<a href="http://www.checkio.org/mission/ip-network-route-summarization/publications/gyahun_dash/python-3/ipv4network/">here</a>). Thank you!

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