How to sort IP addresses

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: How to sort IP addresses by johngg (Canon) on Jan 29, 2007 at 22:02 UTC
One way to do this is with a Schwartzian Transform. Reading the code from bottom to top, read the IPs into a `map` that `chomp`s off the newline then constructs an anonymous array with the IP as first element and it's four parts as the next elements. Pass that anonymous array into the sort routine which does ascending numerical sort on the IP parts, passing the now sorted anonymous list into the next `map`. Finally, `map` the original IP address out in a quoting construct along with a newline and `print`. `use strict; use warnings; print map { qq{$_->[0]\n} } sort { $a->[1] <=> $b->[1] \|\| $a->[2] <=> $b->[2] \|\| $a->[3] <=> $b->[3] \|\| $a->[4] <=> $b->[4] } map { chomp; [ $_, split m{\.} ] } <DATA>; __END__ 192.168.0.12 10.100.16.19 172.192.67.18 192.168.3.2 12.45.66.20 192.168.0.2 10.100.116.19` [download] Here's the output `10.100.16.19 10.100.116.19 12.45.66.20 172.192.67.18 192.168.0.2 192.168.0.12 192.168.3.2` [download] I hope this is of use. Cheers, JohnGG Update: Fixed code indentation.	[reply] [d/l] [select]
Re: How to sort IP addresses by shmem (Chancellor) on Jan 29, 2007 at 22:15 UTC
IP addresses (v4, that is) are four bytes, separated by dots. A sequence like 123.456.789.12 is no valid IP address, since 456 and 789 overflow a byte, which can be 0..255. You can sort IP addresses easily converting them into numbers. There are several ways to do that. You can e.g use the `inet_aton` routine form Socket: `use Socket; my $ip = '127.0.0.1'; print unpack('N', inet_aton($ip)),"\n"; __END__ 2130706433` [download] An equivalent would be `my $ip = '127.0.0.1'; print unpack('N', pack 'C*', split /\./, $ip),"\n"; __END__ 2130706433` [download] Now, for sorting them, you don't want to split / pack / unpack them for every comparison of two items during the sort. So make an list of anonymous arrays holding each `[ $numeric, $ip ]`, sort them via the first element and pull out the second from the sorted list: `use Socket; chomp(my @ips = <DATA>); my @sorted = map { $_->[1] } # pull out second element sort {$a->[0] <=> $b->[0]} # sort list of arrays by first +element map { [ # construct an anonymous array +with a unpack('N',inet_aton($_)), # transformed IP address $_ # and IP address ] } @ips; # your input list print "$_\n" for @sorted; __DATA__ 192.168.10.15 10.24.13.88 172.16.254.13 10.24.13.89 89.67.128.254` [download] Result: `10.24.13.88 10.24.13.89 89.67.128.254 172.16.254.13 192.168.10.15` [download] See Socket, map, sort. Sorting IPs might well be a FAQ... <update> Wrapped `inet_aton` in unpack, `s/chop/chomp/`. Thanks, ikegami. </update> --shmem _($_=" "x(1<<5)."?\n".q·/)Oo. G°\ / /\_¯/(q / ---------------------------- \__(m.====·.(_("always off the crowd"))."· ");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}	[reply] [d/l] [select]
Re^2: How to sort IP addresses by ikegami (Patriarch) on Jan 30, 2007 at 07:03 UTC
I have two bug fixes and a speed enhancement for you. `inet_aton` doesn't return a number, yet you sort numerically. `sort { $a->[0] <=> $b->[0] }` should be `sort { $a->[0] cmp $b->[0] }` `chop` could drop the last char of the data in the file. (e.g. The file could be `"10.0.0.1\n10.0.0.2\n10.0.0.5"`.) Use `chomp` instead of `chop`. It's much faster to avoid creating numerous anonymous arrays and using the default lexical sort, and it's trivial to do here since `inet_aton` returns a fixed length string. See my post for details.	[reply] [d/l] [select]
Re: How to sort IP addresses by ikegami (Patriarch) on Jan 29, 2007 at 22:27 UTC
`inet_aton` returns the address as a 4 byte string. Each byte of the string represents one of the numbers of the IP address. In this format, they can be sorted lexically. `use Socket qw( inet_aton ); use List::MoreUtils qw( apply ); my $file_name = "ipsvisiting.txt"; open (my $fh, '<', $file_name) or die("Unable to open file \"$file_name\": $!\n"); my @sorted = map { substr($_, 4) } sort map { inet_aton($_) . $_ } apply { chomp } <$fh>; print "$_\n" foreach @sorted;` [download] I started writing this when there were no replies, but I got sidetracked. Hopefully, this approach hasn't been suggested already. I made some change to your code: I use the safer 3-arg `open`. I check the result of `open`. I used lexicals where possible.	[reply] [d/l] [select]
Re: How to sort IP addresses by jettero (Monsignor) on Jan 29, 2007 at 21:27 UTC
The secret is to use a sort function. Er, my mistake, you're using one already ... you just need to do a few more comparisons. Perl doesn't have a built in octet comparator for some reason. I use the following little guy a lot, so I just cut and pasted it here. It may help. I call it my ipsort_pipet. Read more... (475 Bytes) -Paul	[reply] [d/l]
Re^2: How to sort IP addresses by mozerd (Initiate) on Apr 28, 2018 at 11:53 UTC
-Paul Thank you very much for your excellent sort ip code --- did the trick for me in a project I was working on -David	[reply]
Re: How to sort IP addresses by McDarren (Abbot) on Jan 30, 2007 at 04:44 UTC
Just for the record, I've been using the following little utility sub for handling IP addresses for a few years now. `sub ipto32bit { # # Convert a dotted quad c.d.e.f to a single unsigned 32bit number. # my ($ip, $c, $d, $e, $f); $ip = shift; ($c,$d,$e,$f) = split(/\./,$ip); return ($c << 24) + ($d << 16) + ($e << 8) + $f; }` [download] Then it's just a matter of doing a straight ~~lexical~~ numerical sort. An example of how this might be used: `#!/usr/bin/perl -wl use strict; chomp(my @ips = <DATA>); my @sorted_ips = sort by_ip(@ips); print for (@sorted_ips); sub by_ip { return ipto32bit($a) <=> ipto32bit($b); } sub ipto32bit { # # Convert a dotted quad c.d.e.f to a single unsigned 32bit number. # my ($ip, $c, $d, $e, $f); $ip = shift; ($c,$d,$e,$f) = split(/\./,$ip); return ($c << 24) + ($d << 16) + ($e << 8) + $f; } __DATA__ 12.345.111.3 12.345.111.26 61.8.47.111 12.345.111.24 203.134.35.27 12.345.111.5 12.345.111.4` [download] Which gives: `12.345.111.3 12.345.111.4 12.345.111.5 12.345.111.24 12.345.111.26 61.8.47.111 203.134.35.27` [download] Note that I started using the above before I learned about the `inet_aton` goodness that was pointed out by shmem above. So if I was looking for a solution now, shmem's is probably the one I would choose. Cheers, Darren :)	[reply] [d/l] [select]
Re: How to sort IP addresses by GrandFather (Saint) on Jan 29, 2007 at 22:34 UTC
Normalise/demormalise: `use strict; use warnings; my @ips = qw(123.156.89.12 12.245.67.1 12.45.67.180 12.145.66.20); @ips = map {sprintf "%d.%d.%d.%d", split /\./} sort map {sprintf "%03d.%03d.%03d.%03d", split /\./} @ips; print join "\n", @ips;` [download] Prints: `12.45.67.180 12.145.66.20 12.245.67.1 123.156.89.12` [download] DWIM is Perl's answer to Gödel	[reply] [d/l] [select]
Re: How to sort IP addresses by AltBlue (Chaplain) on Jan 29, 2007 at 23:07 UTC
TIMTOWTDI ;-) `$ perl -le 'map { printf "%vd\n", $_ } sort map { eval "v$_" } @ARGV' +\ 1.2.1.1 1.1.1.1 1.11.1.1 1.1.1.66 1.1.1.9 1.1.1.1 1.1.1.9 1.1.1.66 1.2.1.1 1.11.1.1` [download] -- AltBlue.	[reply] [d/l]
Re^2: How to sort IP addresses by rinceWind (Monsignor) on Jan 30, 2007 at 10:36 UTC
That's cool! Admittedly, you might be restricted as to perl versions, since it relies on vstring functionality. It occurred to me that there might be a golf like solution involving some kind of GRT. It's probably quite fast as well. I'll even name it for you: the Gutta Percha Transform :). -- Oh Lord, won�t you burn me a Knoppix CD ? My friends all rate Windows, I must disagree. Your powers of persuasion will set them all free, So oh Lord, won�t you burn me a Knoppix CD ? (Missquoting Janis Joplin)	[reply]
Re^3: How to sort IP addresses by AltBlue (Chaplain) on Jan 31, 2007 at 10:37 UTC
Hm, golfing with GRT? No idea how, but anyway, here's a possible starting point: `$ perl -le '$,=$/; print @ARGV[ map { unpack N, substr $_, -4 } \ sort map { eval("v$ARGV[$_]") . pack N, $_ } 0 .. $#ARGV ]' \ 1.2.1.1 1.1.1.1 1.11.1.1 1.1.1.66 1.1.1.9 1.1.1.1 1.1.1.9 1.1.1.66 1.2.1.1 1.11.1.1` [download] OTOH, that previous version could easily be golfed (ok, just a little) by dropping the initial map (which is useful only when using this snippet "for real" - you know, using sprintf and returning a list): `$ perl -e 'printf "%vd\n", $_ for sort map { eval "v$_" } @ARGV' \ 1.2.1.1 1.1.1.1 1.11.1.1 1.1.1.66 1.1.1.9 1.1.1.1 1.1.1.9 1.1.1.66 1.2.1.1 1.11.1.1` [download] -- AltBlue.	[reply] [d/l] [select]
Re: How to sort IP addresses by davorg (Chancellor) on Jan 30, 2007 at 09:40 UTC
This is one of the example sorts in Uri Guttman and Larry Rosler's paper on sorting in Perl. They use the following: `@out = sort { pack('C4' => $a =~ /(\d+)\.(\d+)\.(\d+)\.(\d+)/) cmp pack('C4' => $b =~ /(\d+)\.(\d+)\.(\d+)\.(\d+)/) } @in;` [download] -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re: How to sort IP addresses by Roy Johnson (Monsignor) on Jan 30, 2007 at 02:10 UTC
I think sort::naturally would take care of you. Caution: Contents may have been coded under pressure.	[reply]
Re: How to sort IP addresses by Limbic~Region (Chancellor) on Jan 29, 2007 at 22:31 UTC
Anonymous Monk, Not exactly what you are after, but you might find Sorting a list of IP addresses (aka Why I hate Big O) interesting anyway. Cheers - L~R	[reply]
Re: How to sort IP addresses by smahesh (Pilgrim) on Jan 30, 2007 at 13:19 UTC
Hi, We had to do something similar on one of my earlier projects. This was not in Java not Perl. IIRC, the developer basically converted the IPv4 address from the dotted notation(4 octets) to a number (32 bit number - each octet contributing a byte) and just sorted the numbers and converted them back to IPv4 dotted notation. Maybe you can try the same approach. Hint: Refer to pack/unpack for the conversion from dotted to number and back. Regards, Mahesh	[reply]
Re: How to sort IP addresses by marnix (Initiate) on Aug 10, 2019 at 01:38 UTC
I was actually here to look for some IPV6 sorting code, but reading various IPV4 sorting solutions made me want to add mine from 10 years ago (when I retired). I've forgotten much, but I remember back then being proud of my fairly simple and fast sort of IP addresses. I may have been deluding myself. I hope not, but I'm prepared if so. `#!/usr/bin/env perl chomp(@IPs = <DATA>); @Sorted = map { substr($_, 4) } sort map { pack('C*', split(/\./, $_) ) . $_ } @IPs; print join("\n", @Sorted) . "\n"; __DATA__ 12.345.111.3 12.345.111.26 61.8.47.111 12.345.111.24 203.134.35.27 12.345.111.5 12.345.111.4` [download]	[reply] [d/l]
Re: How to sort IP addresses by chakram88 (Pilgrim) on Jan 29, 2007 at 22:23 UTC
Have you tried the `cmp` operator to compare them as strings? `#! /usr/bin/perl use warnings; use strict; use Data::Dumper; my @ips = qw/ 123.12.255.12 12.255.67.19 255.78.132.255 12.255.67.18 12.245.66.20 123.33.65.89 123.32.65.78 255.78.130.123 123.33.65.78 /; my @sorted_ips = sort {$a cmp $b} @ips; print Dumper \@sorted_ips; ---------- $VAR1 = [ '12.245.66.20', '12.255.67.18', '12.255.67.19', '123.12.255.12', '123.32.65.78', '123.33.65.78', '123.33.65.89', '255.78.130.123', '255.78.132.255' ];` [download]	[reply] [d/l] [select]
Re^2: How to sort IP addresses by GrandFather (Saint) on Jan 29, 2007 at 22:37 UTC
`use strict; use warnings; my @ips = qw(123.156.89.12 12.245.67.1 12.45.67.180 12.145.66.20); @ips = sort {$a cmp $b} @ips; print join "\n", @ips;` [download] Prints: `12.145.66.20 12.245.67.1 12.45.67.180 123.156.89.12` [download] is probably not what OP was after. DWIM is Perl's answer to Gödel	[reply] [d/l] [select]