ruby: how to find non-unique elements in array and print each with number of occurrences?

Question

I have

a = [\"a\", \"d\", \"c\", \"b\", \"b\", \"c\", \"c\"]

and need to print something like (sorted descending by number of occurrences)

Answer 1

This will give you a hash with element => occurrences:

b.reduce(Hash.new(0)) do |hash, element|
  hash[element] += 1
  hash
end