grep for numbers

sandy1028 has asked for the wisdom of the Perl Monks concerning the following question:

When I grep for 'ci=' I got this line and also many other line which has 'ci=' But I have to grep for the line where ci= numbers. for eg: ci=4365345 Can you please tell me how to extract ci=numbers and also remove all the characters before ci and all characters after numbers of ci.

               
             
<body onunload="params='s=o&n=o&ci=5413226&iv=0&pi=34&sessid=c1e7be2e5
+d3518213a67577cf5b2b1c4bd0a0619&uuid=c1e7be2e5d3518213a67577cf5b2b1c4
+bd0a0619&prt=1238476904&pgtp=article&eagi=&t_v=v&">
[download]

How to grep only for

Comment on grep for numbers Download Code

Replies are listed 'Best First'.
Re: grep for numbers by moritz (Cardinal) on Mar 31, 2009 at 06:01 UTC
I recommend reading perlretut, it teaches you the basics about regular expressions that you'll need for this task.	[reply]
Re: grep for numbers by syphilis (Archbishop) on Mar 31, 2009 at 06:18 UTC
Hi sandy1028, Not sure if this helps, but it's very easy to extract the number that follows `ci=` from the example you provided: `use warnings; use strict; no warnings 'numeric'; my $str = q(<body onunload="params='s=o&n=o&ci=5413226&iv=0&pi=34&sess +id=c1e7be2e5d3518213a67577cf5b2b1c4bd0a0619&uuid=c1e7be2e5d3518213a67 +577cf5b2b1c4bd0a0619&prt=1238476904&pgtp=article&eagi=&t_v=v&">); my $num = (split /ci=/, $str)[1] + 0; print $num;` [download] Cheers, Rob	[reply] [d/l] [select]
Re^2: grep for numbers by leonidlm (Pilgrim) on Mar 31, 2009 at 08:06 UTC
Why not to use this one? `my $num = $1 if ($str =~ /ci=(\d+)&/);` [download]	[reply] [d/l]
Re^3: grep for numbers by roboticus (Chancellor) on Mar 31, 2009 at 10:48 UTC
leonidlm: Because it's undefined behavior. It would be better to use: `my $num; $num = $1 if ($str =~ /ci=(\d+)&/);` [download] ...roboticus	[reply] [d/l]
Re: grep for numbers by setebos (Beadle) on Mar 31, 2009 at 08:21 UTC
Something like this (untested) should work: `$data = '<body ...>'; push @data, $1 while $data =~ /ci=(\d+)/g;` [download]	[reply] [d/l]
Re: grep for numbers by bichonfrise74 (Vicar) on Mar 31, 2009 at 18:08 UTC
Another solution... `#!/usr/bin/perl use strict; while( <DATA> ) { print "ci=$1" if /ci=(\d+)/; } __DATA__ <body onunload="params='s=o&n=o&ci=5413226&iv=0&pi=34&sessid=c1e7be2e5 +d3518213a67577cf5b2b1c4bd0a0619&uuid=c1e7be2e5d3518213a67577cf5b2b1c4 +bd0a0619&prt=1238476904&pgtp=article&eagi=&t_v=v&">` [download]	[reply] [d/l]