Whenever you have a variable named after what you plan on putting in it, that's a problem. You want the variable to describe what it holds, not -be- what it holds. You want a hash.

my %teams = map { lc } map { split /:\s+/ } map { chomp; $_ } <DATA>;
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That's probably one of the more "Perlish" ways of writing that. Your datafile's format sucks, which is your problem. Pretty code and sucky input generally don't mix. "A" input gets to play with "A" code. "C" input plays with "C" code. All the special cases.