title: printing certain positions from a matrix
body: <p>If my matrix is like <code>[[1,2,3,4],[5,3,6,2],[7,7,7,2],[9,7,5,3]]</code></p>
  
  <p>and I want to print the positions of the second row so that the output would look something like this:</p>
  
  <pre><code>[1][0]
  [1][1]
  [1][2]
  [1][3]
  </code></pre>
  
  <p>i think i need to use a <code>for</code> loop but not sure exactly how.</p>
  
  <p>thnx</p>