title: Loop with two elements of an array at a time
body: <p>Given this array:</p>
  
  <pre><code>NUMERIC_FIELDS = [:a_single, :a_aggregate,
                    :field_single, :field_aggregate,
                    :line_manager_single, :line_manager_aggregate,
                    :off_single, :off_aggregate,
                    :regional_single, :regional_aggregate]
  </code></pre>
  
  <p>How can I loop over it and pass two elements of it to a method at a time? I should first pass <code>a_single</code> and <code>a_aggregate</code>, then pass <code>field_single</code> and <code>field_aggregate</code>. The method needs to loop only five times as there are five pairs of items.</p>
  
  <pre><code>NUMERIC_FIELDS.each do |column_name|
    are_numeric_fields_valid(column_name)
  end
  </code></pre>