Perl Regex, get strings between two strings - regex

Question

I am new to Perl and trying to use Regex to get a piece of string between two tags that I know will be there in that string. I already tried various answers from stackoverflow but none of them seems to be working for me. Here's my example...
The required data is in $info variable out of which I want to get the useful data
my $info = "random text i do not want\n|BIRTH PLACE=Boston, MA\n|more unwanted random text";
The Useful Data in the above string is Boston, MA. I removed the newlines from the string by $info =~ s/\n//g;. Now $info has this string "random text i do not want|BIRTH PLACE=Boston, MA|more unwanted random text". I thought doing this will help me capture the required data easily.
Please help me in getting the required data. I am sure that the data will always be preceded by |BIRTH PLACE= and succeeded by |. Everything before and after that is unwanted text. If a question like this is already answered please guide me to it as well. Thanks.

Answer 1

Instead of replacing everything around it, you could search for /\|BIRTH PLACE=([^\|]+)\n\|/, [^\|]+ being one or more of anything that is not a pipe.

Answer 2

$info =~ m{\|BIRTH PLACE=(.*?)\|} or die "There is no data in \$info?!";
my $birth_place = $1;
That should do the trick.

Answer 3

You know, actually, those newlines might have helped you. I would have gone for an initial regular expression of:
/^\|BIRTH PLACE=(.*)$/m
Using the multiline modifer (m) to match ^ at the beginning of a line and $ at the end of it, instead of just matching at the beginning and end of the string. Heck, you can even get really crazy and match:
/(?<=^\|BIRTH PLACE=).+$/m
To capture only the information you want, using lookbehind ((?<= ... )) to assert that it's the birth place information.
Why curse the string twice when you can do it once?
So, in perl:
if ($info =~ m/(?<=^\|BIRTH PLACE=).+$/m) {
print "Born in $&.\n";
} else {
print "From parts unknown";
}

Answer 4

You have presumably read this data from a file, which is a bad start. You program should look like this
use strict;
use warnings;
use autodie;
open my $fh, '<', 'myfile';
my $pob;
while (<$fh>) {
if (/BIRTH PLACE=(.+)/) {
$pob = $1;
last;
}
}
print $pob;
output
Boston, MA