From: matu <m@...>
Date: 2008-07-30T06:19:28+09:00
Subject: the old sorting ip addresses problem

i am sure there has to be some ruby way of doing this in a really simple way...
i came up with this, but i am sure there is some other way that is much cleaner.

>> a = ["5.100.200.50", "10.150.50.1", "10.150.50.2", "10.150.51.1", "19.18.16.15", "192.168.0.1"]
=> ["5.100.200.50", "10.150.50.1", "10.150.50.2", "10.150.51.1", "19.18.16.15", "192.168.0.1"]
>> a.sort {|a1, a2| y = [a1, a2].map {|addr| x = 0; addr.split('.').reverse.each_with_index {|n, i| x = x + n.to_i * (256 ** (i))}; x}; y.last <=> y.first}
=> ["192.168.0.1", "19.18.16.15", "10.150.51.1", "10.150.50.2", "10.150.50.1", "5.100.200.50"]
>>