title: python datetime to excel serial number
body: <p>How to convert (YY,MM,DD,HH,MM,SS) to the Excel "serial" datetime number.</p>
  
  <p>Example: 12/23/2017  10:00:00 PM to 43092.91667</p>
  
  <p>Below converts the date only, but I need to add the timestamp as well:</p>
  
  <pre><code>def convertDateToExcel(day, month, year) :
      offset = 693594
      itime = date(year,month,day)
      n = itime.toordinal()
      return (n - offset)
  </code></pre>