?? List::AllUtils::http://search.cpan.org/perldoc/List::AllUtils#any_BLOCK_LIST#any?

use List::AllUtils qw/ any /;
sub is_in_num {
  my( $num, $list ) = @_;
  return any { $num == $_ } @$list;
}
sub is_in_str {
  my( $str, $list ) = @_;
  return any { $str eq $_ } @$list;
}
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Smart matching?? http://perldoc.perl.org/perlop.html#Smartmatch-Operator

use 5.010;
*is_in_num = *is_in_str = sub {
  my( $str, $list ) = @_;
  return $str ~~ $list;
};
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