each

Yields all elements of the matrix, starting with those of the first row, or returns an Enumerator is no block given. Elements can be restricted by passing an argument:

• :all (default): yields all elements

• :diagonal: yields only elements on the diagonal

• :off_diagonal: yields all elements except on the diagonal

• :lower: yields only elements on or below the diagonal

• :strict_lower: yields only elements below the diagonal

• :strict_upper: yields only elements above the diagonal

• :upper: yields only elements on or above the diagonal

  Matrix[ [1,2], [3,4] ].each { |e| puts e }

  # => prints the numbers 1 to 4
  

  Matrix[ [1,2], [3,4] ].each(:strict_lower).to_a # => [3]