if( grep { $a == $a[$_] && $b eq $b[$_] } 0 .. $#a ) {
  # do stuff here
}
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Update: and here's the cleaner approach using List::Util's first (as kindly pointed out by Zed_Lopez below)

if( first { $a == $a[$_] && $b eq $b[$_] } 0 .. $#a ) {
  # do stuff here
}
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List::Util's first function will work, too, with the advantage of exiting as soon as something's found, saving the computation of searching all of both lists every time.

As does the OP's already existant solution :)

duff

The only thing "clunky" about it IMHO is the synthetic variable $found and even that's not so bad. You could the code it in a sub to isolate it a bit:

# note, assumes we're in a scope that knows about @a and @b
sub check_a_b {
   my ($a,$b) = @_;
   for (0..$#a) { return 1 if $a eq $a[$_] && $b eq $b[$_]; }
   return 0;
}
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Or you could transmogrify the arrays to hashes but if you're updating the arrays throughout the code, you'll have to update the hashes too and that can be a bit of a pain.

unless (exists { map { $a[$_].$b[$_] => $_ } 0..$#a }->{$a.$b}) {
   do_something();
}
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%ab = map { $a[$_].$b[$_] => $_ } 0..$#a;
...
unless (exists $ab{$a.$b}) { do_something() }
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my @a = qw(1 11);
my @b = qw(1a 2b);

($a,$b) = qw(11 a);
print "Why am I printing?$/" unless (exists { map { $a[$_].$b[$_] => $
+_ } 0..$#a }->{$a.$b});
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Of course, if you can guarantee @a contains only numerals and @b contains no numerals, then your solution works as advertised. However, this solution does break down when either array can contain any character.

Thanks for pointing that out. I was going to mention the limitation, but decided the OP's example was sufficiently exemplary.

First, you skip index 0. Second, if anyone modifies $[, your @a-1 won't be the last element. Anyhow, let's take a crack at it:

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

my @a = qw(1  2  1  1  2  2  1  2);
my @b = qw(aa aa ab ac ac ad ac ad);

print "first" if find_pair(1,"aa",\@a,\@b);
print "not printed" if find_pair(2,"ax",\@a,\@b);
print "not printed" if find_pair(4,"ax",\@a,\@b);
print "second" if find_pair(2,"ac",\@a,\@b);
print "third" if find_pair(2,"ad",\@a,\@b);

sub find_pair {
  my ($first,$second,$array1,$array2) = @_;
  $first eq $array1->[$_] && $second eq $array2->[$_] && return 1 for 
+$[..$#$array1
}

__END__
first
second
third
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FWIW, using $a and $b as variable names in non-example code can get confusing pretty fast, especially if you're writing any sort routines.

use warnings;
use strict;

our @arr_1 = qw/  1  1  2  1  1  2  2  1  2 /;
our @arr_2 = qw/ ab aa aa ab ac ac ad ac ac /;

my ( $input1, $input2 ) = ( 1, 'ab' );
my ( $input3, $input4 ) = ( 1, 'ad' );

print "test1: ", find_match ( $input1, $input2 ), "\n";
print "test2: ", find_match ( $input3, $input4 ), "\n";

#unless ( find_match ( search pair ) ) { do something }

sub find_match {
    my ( $in1, $in2 ) = @_;
    return scalar
        grep { $in1 eq $arr_1[$_] && $in2 eq $arr_2[$_] } 0..scalar @a
+rr_1 - 1;
}
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