for each element in @b
   $a[1] = element
   print $a[1]
done

##</code><code>##

@a = (1,2,3);
@b = (2,4,6,7);
print for @b[@a]; # print for elements of @b with indexes in @a

##</code><code>##

@a = (1,2,3);
@b = (2,4,6,7);
for $i (@a)
{
   print $b[$i];
}