my $regex = '\b(' + join('|', @nums) + ')\b';

Still the whole addition/concatenation problem.

Also, moving the capture into  $regex doesn't address multiple captures per line. This may not even be a possibility in the OPer's application (nothing is ever said about this), but I like to defend against things like this.

Does this fix it?

        for my $m (m/$regex/g) { # Update: reworked 
            $matched{$m} = 1;
            print "$file $_";
        }
[download]

Full code:

#!/usr/bin/env perl

use strict;
use warnings;

my @files = <c:/perl64/myfiles/*>;

# record matching regexes
our %matched;

my @nums = ('1203', '1204', '1207');
my $regex = '\b(' . join('|', @nums) . ')\b'; # update: fixed + to .

for my $file ( @files ) {

    open my $file_h, '<', $file or die "Can't open $file: $!";

    while ( <$file_h> ) {
        for my $m (m/$regex/g) { # Update: reworked 
            $matched{$m} = 1;
            print "$file $_";
        }
    }
}

# Check all nums have been seen
for my $num (@nums) {
    if (not exists($matched{$num})) {
        print "$num not found\n";
    }
}
[download]

-QM
--
Quantum Mechanics: The dreams stuff is made of

What Anonymous Monk said:

while (my ($match) = m/$regex/g) {
    $matched{$match} = 1;
    print "$file $_";
}
[download]

gives you an infinite loop.

c:\@Work\Perl\monks>perl -wMstrict -le
"my $regex = qr{ \b f[eio]e \b }xms;
 ;;
 $_ = 'xx fee fie foe yy';
 while (m/($regex)/g) {
   my $match = $1;
   print qq{captured '$match'};
   }
"
captured 'fee'
captured 'fie'
captured 'foe'
[download]

works better (at least it stops). If you want to get a bit fancy,

while (m/($regex)/g and my $match = $1) {
  print qq{captured '$match'};
  }
[download]

also works. But the whole "extract multiple matches per line" thing may not even be a real issue! The OPer says nothing about it, and I only raised it as a cautionary point of interest.

---

Give a man a fish:  <%-{-{-{-<

Fixed original.

-QM
--
Quantum Mechanics: The dreams stuff is made of

this matches, but loops infinitly on the same line print, the script never finishes

running the script, looks like its trying to convert the code to numbers

 
Argument "1213|1204|1207" isn't numeric in addition (+) at newcheck.pl
+ line 12.
Argument "\\b(" isn't numeric in addition (+) at newcheck.pl line 12.
Argument ")\\b" isn't numeric in addition (+) at newcheck.pl line 12.
[download]

... looks like its trying to convert the code to numbers

That's because addition is a numeric operation.

---

Give a man a fish:  <%-{-{-{-<

Ack, too much Python lately, apologies.

my $regex = '\b(?:' . join('|', @nums) . ')\b';
[download]

-QM
--
Quantum Mechanics: The dreams stuff is made of

tried this one, when one of the numbers is matched in a file it keeps printing it over and over on the screen .. so the script never finishes