@keys = qw(one two five);
unshift @keys,'four';
print "@keys\n";
if (@hash{@keys}) {
    print "yep\n";
} else {
    print "nope\n";
}
 
@keys = qw(one two five);
push @keys, 'two';
print "@keys\n";
if (@hash{@keys}) {
    print "yep\n";
} else {
    print "nope\n";
}

##</code><code>##

four one two five
yep
one two five two
nope 

##</code><code>##

if ( grep{ exists( $hash{$_} ) } @keys ) { 
    print "yep\n";
} else {
    print "nope\n";
}