I think this is what you want:

#!/usr/bin/perl -w
use strict;

my $string = "Field1:  one";

my @regex;
push(@regex, qr/Field1:  (\w{3})/);
push(@regex, qr/Field2:  (\w{3})/);
push(@regex, qr/Field3:  (\w{3})/);

foreach (@regex) {
 if ($string =~ $_ ) {
  print "$1\n";
 }
}
[download]

Note that I changed the conditional in the foreach loop so that it would print only if the match was successful rather than in $1 was defined, which in this case after the first match continues to be defined.

-enlil