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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.
Great solution! Where is the 'no way' being used?
Lovely! Tips hat
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Is there documentation that covers this topic in more detail? I understand the difference between an instance variable and a local variable, but I'm still not sure why it is much faster. I also noticed that the conditional assignment speeds the process up as well. Why is that?
This doesn't work for all cases. #group_by is not case sensitive.
EX: ["a", "A", "B", "b"].group_by { |x| x.downcase }