Not a 'smart' way.. but here goes: 
use strict;

my @a=qw(a b c d);
my @b=qw(b a e f);

# this does exactly what your pair of 'for' loops 
# did...
my @m = map {
    my $x = $_;
    grep { /^$x$/ } @b;      
} @a;
 
print @m;
print "\n";

[download]
Prints output: 
ab

[download]


UPDATE 1: A slightly 'smarter' alternative here ;) 
use strict;

my @a=qw(a b c d);
my @b=qw(b a e f);

my %h;
my @m = map {$h{$_}++ ? $_ : ()} (@a, @b);
 
print @m;
print "\n";

[download]
This time, I'm using a hash to keep count of number of tiems a value is found in both arrays. For any value that's been counted more than once, I dump it into the @m array.

_____________________ 
$"=q;grep;;$,=q"grep";for(`find . -name ".saves*~"`){s;$/;;;/(.*-(\d+)
+-.*)$/;
$_=["ps -e -o pid | "," $2 | "," -v "," "];`@$_`?{print"+ $1"}:{print"
+- $1"}&&`rm $1`;
print$\;}

[download]

In reply to Re: any smart ideas??:) by vladb
in thread Comparing two arrays (was: any smart ideas??:) by Anonymous Monk

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