Ranges

ranges.rb

input = [1, 2, 3, 8, 9, 10, 21, 22, 23, 24]

def scan(input)

  min, max = input[0], input[1]
  output = []

  input.each_with_index do |current, index|
    next if index == 0

    previous = input[index-1]

    if (current - previous == 1)
      # continue
    else
      output << "#{min}..#{previous}"
      min = current
    end

  end

  output << "#{min}..#{input.last}"

  output
end

output = scan(input)

puts output.inspect

# => ["1..3", "8..10", "21..24"]