Greetings sandrider,

In addition to using labels as two other monks have suggested already, you could use last to exit the inner loop, thus nexting to the outer loop.

foreach my $one (@one) {
    $one =~ m/\(.\)(.+)\(.\)/;
    foreach my $two (@two) {
        if (($1) and ($two eq $1)) {
            push @result, $one;
            last;
        }
    }
}
[download]

TMTOWTDI.

Update: I moved the m// outside the inner foreach due to japhy's comment. No idea why I didn't see that before. Doh.

This solution, of course, doesn't help with existing deeply nested loops. That's where the labels come in really handy. There is the caveat that the misuse of labels can cause very odd behavior (like the sudden termination of you script) if you are not careful (typos).

Also, to further optimize (typing optimization; not necessarily execution optimization) based on japhy's comment, you could try this instead:

push @results, grep {
    grep { $1 eq $_ } @two if ( $_ =~ /\(.\)(.+)\(.\)/ )
} @one;
[download]

You get to use a nested grep, but you check all values of @two and don't stop when you find a match.

Update: Since grep will localize $_ and I don't need the outer $_ in the inner grep, I optimized away reassigning the outer $_;

Ivan Heffner
Sr. Software Engineer, DAS Lead
WhitePages.com, Inc.

Use labels:

PARENT: foreach $one (@one) {
  foreach $two (@two) {
    $one =~ m/\(.\)(.+)\(.\)/;

    if ($two eq $1) {
      push @result, $one;
      next PARENT;
    }
  }
}
[download]

Odd are, at least three other people will post the exact same thing before I hit 'create'

See "Loop Control" in perlsyn

Move the $one =~ m/.../ line outside of the inner for-loop. There's no reason to do the same thing over and over and over.