Perl regex exclude optional word from match - regex

Question

I have a strings and need to extract only icnnumbers/numbers from them.
icnnumber:9876AB54321_IN
number:987654321FR
icnnumber:987654321YQ
I need to extract below data from above example.
9876AB54321
987654321FR
987654321YQ
Here is my regex, but its working for first line of data.
(icnnumber|number):(\w+)(?:_IN)
How can I have expression which would match for three set of data.

Answer 1

Given your strings to extract are only upper case and numeric, why use \w when that also matches _?
How about just matching:
#!/usr/bin/env perl
use strict;
use warnings;
while (<DATA>) {
m/number:([A-Z0-9]+)/;
print "$1\n";
}
__DATA__
icnnumber:9876AB54321_IN
number:987654321FR
icnnumber:987654321YQ

Answer 2

Another alternative to get only the values as a match using \K to reset the match buffer
\b(?:icn)?number:\K[^\W_]+
Regex demo | Perl demo
For example
my $str = 'icnnumber:9876AB54321_IN
number:987654321FR
icnnumber:987654321YQ';
while($str =~ /\b(?:icn)?number:\K[^\W_]+/g ) {
print $& . "\n";
}
Output
9876AB54321
987654321FR
987654321YQ

Answer 3

You may replace \w (that matches letters, digits and underscores) with [^\W_] that is almost the same, but does not match underscores:
(icnnumber|number):([^\W_]+)
See the regex demo.
If you want to make sure icnnumber and number are matched as whole words, you may add a word boundary at the start:
\b(icnnumber|number):([^\W_]+)
^^
You may even refactor the pattern a bit in order not to repeat number using an optional non-capturing group, see below:
\b((?:icn)?number):([^\W_]+)
^^^^^^^^
Pattern details
\b - a word boundary (immediately to the right, there must be start of string or a char other than letter, digit or _)
((?:icn)?number) - Group 1: an optional sequence of icn substring and then number substring
: - a : char
([^\W_]+) - Group 2: one or more letters or digits.

Answer 4

Just another suggestion maybe, but if your strings are always valid, you may consider just to split on a character class and pull the second index from the resulting array:
my $string= "number:987654321FR";
my #part = (split /[:_]/, $string)[1];
print #part
Or for the whole array of strings:
#Array = ("icnnumber:9876AB54321_IN", "number:987654321FR", "icnnumber:987654321YQ");
foreach (#Array)
{
my $el = (split /[:_]/, $_)[1];
print "$el\n"
}
Results in:
9876AB54321
987654321FR
987654321YQ

Answer 5

Regular expression can have 'icn' as an option and part of the interest is 11 characters after :.
my $re = qr/(icn)?number:(.{11})/;
Test code snippet
use strict;
use warnings;
use feature 'say';
my $re = qr/(icn)?number:(.{11})/;
while(<DATA>) {
say $2 if /$re/;
}
__DATA__
icnnumber:9876AB54321_IN
number:987654321FR
icnnumber:987654321YQ
Output
9876AB54321
987654321FR
987654321YQ

Answer 6

Already you got best and better answers here anyway I trying to solve your question right now.
Get the whole string,
my $str = do { local $/; <DATA> }; #print $str;
You can check the first grouping method upto _ or \b from the below line,
#arrs = ($str=~m/number\:((?:(?!\_).)*)(?:\b|\_)/ig);
(or)
You can check the non-words \W and _ for the first grouping here, and pushing the matches in the array
#arrs = ($str=~m/number\:([^\W\_]+)(?:\_|\b)/ig);
print the output
print join "\n", #arrs;
__DATA__
icnnumber:9876AB54321_IN
number:987654321FR
icnnumber:987654321YQ