Building a Histogram : Enumerable « Collections « Ruby

1. Ruby
2. Collections
3. Enumerable

Building a Histogram

module Enumerable
  def to_histogram
    inject(Hash.new(0)) { |h, x| h[x] += 1; h}
  end
end

p [1, 2, 2, 2, 3, 3].to_histogram
# => {1=>1, 2=>3, 3=>2}

p ["a", "b", nil, "c", "b", nil, "a"].to_histogram
# => {"a"=>2, "b"=>2, "c"=>1, nil=>2}

 

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