my @files = qw{ Date12_type.asp Date1_type.asp Date7_type.asp Date4_type.asp };

my @sorted_files = map  { join '', @{$_} }
                   sort { $a->[1] <=> $b->[1] }
                   map  { [(/([^\d]+)(\d+)(.*)/)] } @files;
$,="\n";
print @sorted_files;