eek.rb

x = [[1, nil, 50],
     [1, 23, nil],
     [2, 55, nil],
     [4, 5, nil],
     [4, nil, 62]]

expected_dates = *1..5

expected_dates.map do |date|
  @hash[date] = []
end

@actual_dates = []

x.each { |error| @actual_dates << error.first }

expected_dates.each do |k, v|
  @results ||= []
  
  case @actual_dates.count k
  when 0
    @results << [k, 0, 0]
  when 1
    @results << [k, 'first match', 0]
  when 2
    @results << [k, 'first match', 'second match']
  end
end

@results

#=> [[5, 0, 0],
 [1, "first match", "second match"],
 [2, "first match", 0],
 [3, 0, 0],
 [4, "first match", "second match"],
 [5, 0, 0]]