split split

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

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Re: split split by locked_user sundialsvc4 (Abbot) on Jun 23, 2009 at 16:10 UTC
(Shrug...) What you've got now is clear and it works. What's not to luv? Please give me code that is “clear,” any day, over code that is “clever.” I can look at your example and instantly comprehend how it works. I can also tweak it without too much fear of breaking it. That, to me, is a very compelling argument in favor of what you started with.
Re: split split by davorg (Chancellor) on Jun 23, 2009 at 16:03 UTC
Pretty close. I think you want: `(split /#/)[0]` [download] -- See the Copyright notice on my home node. Perl training courses	[reply] [d/l]
Re: split split by suaveant (Parson) on Jun 23, 2009 at 16:17 UTC
Split is usually used for breaking up a string, for pulling a specific piece of a string out usually a regexp is a better bet `if($string = /^client\s+(\d+\.\d+\.\d+\.\d+)/) { $ipaddr = $1; } else { die 'horribly'; }` [download] - Ant - Some of my best work - (1 2 3)	[reply] [d/l]
Re: split split by oko1 (Deacon) on Jun 23, 2009 at 16:21 UTC
You can specify multiple delimiters for 'split': `while (<FH>){ print +(split /#\|\s/)[1]; }` [download] -- "Language shapes the way we think, and determines what we can think about." -- B. L. Whorf	[reply] [d/l]
Re: split split by artist (Parson) on Jun 23, 2009 at 21:56 UTC
If you really need the 'ip address', you can use the right expression. `use Regexp::Common qw/net/; + my $ip_regexp = qr($RE{net {IPv4}); + while(<DATA>) { + if (/($ip_regexp)/) { + my $ip_address = $1; + print "$ip_address\n"; + } + } + + __DATA__ + client 127.0.0.1#47560: query: host.example.com IN AAAA +` [download] --Artist	[reply] [d/l]
Re: split split by moritz (Cardinal) on Jun 23, 2009 at 16:05 UTC
`$ perl -wle 'print +(split /#/, "a#b")[1];' b` [download] You can also use undef where you don't want variable names: `my (undef, $a) = split ...` [download]	[reply] [d/l] [select]
Re: split split by toolic (Bishop) on Jun 23, 2009 at 16:12 UTC
You can split split, but it may not be the best solution: `use strict; use warnings; while (<DATA>) { my $ipaddr = (split /\s+/, (split /#/, $_)[0])[1]; print "ipaddr = $ipaddr\n"; } __DATA__ client 127.0.0.1#47560: query: host.example.com IN AAAA +` [download] prints: `ipaddr = 127.0.0.1` [download]	[reply] [d/l] [select]
Re: split split by FunkyMonk (Bishop) on Jun 23, 2009 at 19:05 UTC
And another way... You want the stuff between the first space and the first hash `$_ = "client 127.0.0.1#47560: query: host.example.com IN AAAA +"; (my $ip) = /\s(.*?)#/; print $ip; #127.0.0.1` [download] Unless I state otherwise, all my code runs with strict and warnings	[reply] [d/l]
Re: split split by Marshall (Canon) on Jun 23, 2009 at 17:36 UTC
You are very close and I don't see anything wrong with this approach. The first split is in a list context and there is no need to assign "junk". The 2nd split should also be put into a list context and then just take the 2nd thing via a "list slice", `[1]` subscript. See below.. `#!/usr/bin/perl -w use strict; my $line = 'client 127.0.0.1#47560: query: host.example.com IN AAAA'; my ( $part1) = split (/#/,$line); my ( $ipaddr ) = (split(/\s+/, $part1))[1]; print " part1: $part1\n ipaddr: $ipaddr\n"; __END__ Prints: part1: client 127.0.0.1 ipaddr: 127.0.0.1` [download] Occasionally you will see: `(undef, my $ipaddr) = split(/\s+/, $part1);` [download] And although that will work, I wouldn't use it. Assigning something to undef as a lvalue "throws it in the bit bucket". I think it is "cleaner" to use the slice. Update: Now of course, if you just want the IP address: `my $line = 'client 127.0.0.1#47560: query: host.example.com IN AAAA'; (my $ipaddr) = (split/[\s#]/,$line)[1]; print "$ipaddr\n"; __END__ prints: 127.0.0.1` [download]	[reply] [d/l] [select]
Re: split split by linuxer (Curate) on Jun 23, 2009 at 17:42 UTC
If you are sure about the format of your input data (order of fields, number of whitespaces, ...), you can try something like this: `my $line = 'client 127.0.0.1#47560: query: host.example.com IN AAAA +' +; my ( $ip, $host ) = ( split /[ #]/, $line, 6 )[1,4]; print "IP: $ip, HOST: $host\n";` [download]	[reply] [d/l]