I actually was working on a hash-based solution first, using group_by, but I switched to using just array after seeing the Python version. I didn't really think

I actually was working on a hash-based solution first, using group_by, but I switched to using just array after seeing the Python version. I didn't really think about the time complexity of the count operation inside the sort_by operation, thanks for pointing that out. You definitely can do a hash-based solution in a single expression in Ruby. Here's a very ugly and kludgy example that you could probably improve on if you wanted to. I don't think it's n^2 because the group_by just counts the occurrences of each word and returns a hash where the count is the key: str.split.group_by{|w| str.split.count(w)}.sort_by{|k,v| k}.reverse.flatten.uniq.keep_if{|w| w.is_a?(String)}.take(10) I'm also trying to work out a better way to do this using "chunk" because although hashes are fast to access, they are not fundamentally sortable, and sort_by returns a 2d array just like chunk does anyway.