Safe transpose method, to avoid IndexErrors with non-rectangular multidimensional arrays

safe_transpose.rb

# Safe transpose method, to avoid IndexErrors with non-rectangular multidimensional arrays
# >> a = [[1,2], [3,4], [5]]
# >> puts a.transpose.inspect
# [[1, 3, 5], [2, 4, nil]]
class Array
  def safe_transpose
    result = []
    max_size = self.max { |a,b| a.size <=> b.size }.size
    max_size.times do |i|
      result[i] = Array.new(self.first.size)
      self.each_with_index { |r,j| result[i][j] = r[i] }
    end
    result
  end
end