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Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
I was about to post this purplemath link. Mathematically challenged, I found it more helpful than the link in the instructions.
The short answer is, It's a Positive Lookahead (zero-width assertion). look ahead for 'space' (or end of $tring) without including it in the result. Good Job on this kata.
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