title: Painting rows based on value,using only 2 colours
body: <p>Imagine we have a grid such as:</p>
  
  <pre><code>Column1       Column2 ....
  A             432423
  A             344
  A             5
  B             45
  B             77
  C             65
  D             4
  D             545
  .             .
  .             .
  .             .
  </code></pre>
  
  <p>I want to paint these rows based on the value on Column1,we don't know the values(so conditional formatting is not possible) they could be anything,but i just want to group them by color,for example I want the rows that have A in Column1 to be pink,then rows with B yellow then with C pink again and D yellow and so on.What kinda iteration could i use?</p>