If both the new and the old value at the same time (e.g. if you want to call rename), the soluton in this post's parent can be refactored as:

@old_names = (
   22200010001, 22200010101, 22200010102, 22200010103, 22200010201
);

foreach (@old_names) {
   my $old_name = $_;
   my $new_name = $_ - 9900;

   ... do something ...
}
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