title: How to convert Excel sheet column names into numbers?
body: <p>I was wondering what is the best way to convert excel sheet column names into numbers.</p>
  
  <p>I'm working with <a href="http://www.codeplex.com/ExcelPackage/" rel="noreferrer">Excel Package</a>, a good library to handle .xlsx documents. This library unfortunately doesn't have this functionality included.</p>
  
  <blockquote>
    <p>OBS: The first column, A, corresponds
    to number 1 in this library.</p>
  </blockquote>