Hash values as arrays

gistfile1.txt

  @avg_score_hash = Hash.new { |hash, key| hash[key] = [] } 
  @rows.each do |row|
    row.last.each_with_index do |column, index|
      if column != 0
        @avg_score_hash[index] << column
      end
    end
  end
  @avg_score_hash  
  
#=> {2=>[92.73], 5=>[90.91, 95.56, 90.91], 3=>[93.33], 0=>[100.0]}
@avg_score_hash.map { |k,v| [k, [v.sum/v.size]]}.to_h
#=> {2=>[92.73], 5=>[92.46], 3=>[93.33], 0=>[100.0]}