How to findout a sub string from the string

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

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Re: How to findout a sub string from the string by davido (Cardinal) on Feb 13, 2016 at 19:38 UTC
For your simple specification you really only need to find the final newline and capture through the end of the string. A regular expression isn't needed for that: `my $found = substr $tmp, rindex($tmp, "\n")+1; print "$found\n";` [download] This solution would translate with minor changes to almost any language. A regular expression would let you get more fancy in what you gather without the code becoming unmanagable. `my $tmp = "1: 2\n2: /my/tmp/20160213T161519/outgoing\n3: DL\n4: 0\nTem +pSource: , Ue: 2, TaskName=, TempDest: \nTaskName \n/data/busybox/ps +\|grep mgen5\| grep -v grep\nDL txt is running PID: 3848\nRunning:Mgen: +3848"; my @fields = qw(All Value Name Process_ID); my %substr; @substr{@fields} = $tmp =~ m/\n(Running:(([^:]+):(\d+)))(?:\D\|$)/; printf "%-12s[%s]\n", $_, $substr{$_} for @fields;` [download] This produces... `All [Running:Mgen:3848] Value [Mgen:3848] Name [Mgen] Process_ID [3848]` [download] Dave	[reply] [d/l] [select]
Re^2: How to findout a sub string from the string by Discipulus (Canon) on Feb 13, 2016 at 22:00 UTC
wow and ++davido; the regexed monk offered a pre regex (clean and neet) solution using rindex ;=) shame on me 'cause i never seen `rindex` before L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply]
Re^3: How to findout a sub string from the string by davido (Cardinal) on Feb 14, 2016 at 04:39 UTC
:) Well to be fair I first toyed with using reverse and index, before thinking to myself... "hmmm... I seem to remember rindex being a thing." I wasn't immediately certain that my recollection of rindex came from Perl or another language. Most common languages probably provide something similar. Dave	[reply]
Re: How to findout a sub string from the string by Laurent_R (Canon) on Feb 13, 2016 at 18:27 UTC
You need to say more on how to determine what you want to extract. Assuming you want to extract the last line of the string (i.e. everything after the last `\n`), you could use split and retrieve the last field: `my $substring = (split /\n/, $tmp)[-1];` [download] Or use a regular expression: `my ($substring) = $tmp =~ /\n(.*)$/;` [download]	[reply] [d/l] [select]
Re: How to findout a sub string from the string by Discipulus (Canon) on Feb 13, 2016 at 17:54 UTC
welcome gjoshi peraphs you want to use a regex (regular expression) to to this kind of job. perlrequick gives you the basic, while `perlretut` is a longer introduction to the matter. Pay attention with `\n` newlines in your data: normally the `.` dot does not match them. If you capture with `(your pattern)` parens then you'll have results stored into `$1` ( `$2` .. etc) see `perlvar` In my homenode you can find some tool to play with regexes online or offline. L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l] [select]
Re^2: How to findout a sub string from the string by AnomalousMonk (Archbishop) on Feb 13, 2016 at 19:04 UTC
Don't forget the Holy Book itself: perlre. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l]