How do I extract the data that comes after a certain word?

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

Replies are listed 'Best First'.
Re: How do I extract the data that comes after a certain word? by ikegami (Patriarch) on Jun 18, 2012 at 19:55 UTC
First, previous answers use `$1`, but I hate using global variables when it's not necessary. It's not necessary here. Second, previous answers assume you don't want to capture newlines, but you didn't say anything of the kind. Fix: `if (my ($match) = $s =~ /yesterday (.?) after/s) { say $match; }` [download] Finally, using the `?` greediness modifier can lead to surprises (especially if you use more than one in a single pattern). If given `yesterday foo yesterday bar after` [download] the above regex will capture `foo yesterday bar` [download] If you want `bar` [download] use the following instead: `if (my ($match) = $s =~ /hello ((?:(?!yesterday).)) yesterday/s) { say $match; }` [download] `(?:(?!STRING).)` is to `STRING` as `[^CHAR]` is to `CHAR`.	[reply] [d/l] [select]
Re: How do I extract the data that comes after a certain word? by tobyink (Canon) on Jun 18, 2012 at 19:34 UTC
This is probably the simplest way... `my $String = "hello I went to the store yesterday and the day after an +d the day after"; if ($String =~ m{yesterday .+? after}) { print $&; }` [download] perlvar warns though that use of `$&` can slow down your script considerably. If it's a small script and raw speed is not your prime concern, this is probably acceptable. If performance does become a concern though, the following should also do the trick and is almost as readable... `my $String = "hello I went to the store yesterday and the day after an +d the day after"; if ($String =~ m{(yesterday .+? after)}) { print $1; }` [download] `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l] [select]
Re: How do I extract the data that comes after a certain word? by 2teez (Vicar) on Jun 18, 2012 at 19:46 UTC
Why use Perl $POSTMATCH or $'. when you can easily do like so: `my $string='hello I went to the store yesterday and the day after an +d the day after'; if($string=~m/.+?(yesterday.+?after).+?$/i){ print 'Summary: ',$1,$/; ## print yesterday and the da +y after }` [download] Please check the following for some details. perldoc -v $` perldoc -v $& perldoc -v $'	[reply] [d/l]
Re^2: How do I extract the data that comes after a certain word? by MiriamH (Novice) on Jun 19, 2012 at 14:58 UTC
Whenever I try to modify this script to work for a much larger string, nothing happens. I think its because the words "Summary" and "Description" (Which is what I'm scraping between in my real script) keep on repeating. Is there a way to write it as a foreach loop to make it keep going through the script and writing everything it seems between the words "summary" and "description" every time its written??	[reply]