title: Removing all elements of a column in a two-dimensional array
body: <p>I have this array:</p>
  
  <pre><code>arr = [["a","b","c"],[2,3,5],[3,6,8],[1,3,1]]
  </code></pre>
  
  <p>which is representing a prawn-table containing columns "a", "b", and "c".</p>
  
  <p>How do I remove the entire column "c" with all its values, 5, 8, 1?</p>
  
  <p>Maybe there are useful hints in "<a href="https://stackoverflow.com/questions/1720932/create-two-dimensional-arrays-and-access-sub-arrays-in-ruby">Create two-dimensional arrays and access sub-arrays in Ruby</a>" and "<a href="https://stackoverflow.com/questions/4012666/difficulty-modifying-two-dimensional-ruby-array">difficulty modifying two dimensional ruby array</a>" but I can't transfer them to my problem.</p>