my @keys = qw(
	3242_38
	2313_44
	3242_37
	3518_38
	3242_49
	3518_44
	);

map { print "$_\n" } reverse @keys;

##</code><code>##

3518_44
3518_38
3242_49
3242_38
3242_37
2313_44

##</code><code>##

3518_44
3242_49
3518_38
3242_37
2313_44
3242_38