method

each

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What's this?

each(which = :all) public

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]

Show source

# File lib/matrix.rb, line 402
  def each(which = :all) # :yield: e
    return to_enum :each, which unless block_given?
    last = column_size - 1
    case which
    when :all
      block = Proc.new
      @rows.each do |row|
        row.each(&block)
      end
    when :diagonal
      @rows.each_with_index do |row, row_index|
        yield row.fetch(row_index){return self}
      end
    when :off_diagonal
      @rows.each_with_index do |row, row_index|
        column_size.times do |col_index|
          yield row[col_index] unless row_index == col_index
        end
      end
    when :lower
      @rows.each_with_index do |row, row_index|
        0.upto([row_index, last].min) do |col_index|
          yield row[col_index]
        end
      end
    when :strict_lower
      @rows.each_with_index do |row, row_index|
        [row_index, column_size].min.times do |col_index|
          yield row[col_index]
        end
      end
    when :strict_upper
      @rows.each_with_index do |row, row_index|
        (row_index+1).upto(last) do |col_index|
          yield row[col_index]
        end
      end
    when :upper
      @rows.each_with_index do |row, row_index|
        row_index.upto(last) do |col_index|
          yield row[col_index]
        end
      end
    else
      Matrix.Raise ArgumentError, "expected #{which.inspect} to be one of :all, :diagonal, :off_diagonal, :lower, :strict_lower, :strict_upper or :upper"
    end
    self
  end

each

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