You can't know something before you know it, unless you use Time::Machine.

Time to rethink your algorithm. Say in english what you want to do. Avoid the word "loop" or "array". Just talk about what you want done, because you are now hopelessly down in the guts of the implementation with muddy thinking, and no-one can help you from there.

-- Randal L. Schwartz, Perl hacker