title: How to write to an existing excel file without overwriting data (using pandas)?
body: <p>I use pandas to write to excel file in the following fashion:</p>
  
  <pre><code>import pandas
  
  writer = pandas.ExcelWriter('Masterfile.xlsx') 
  
  data_filtered.to_excel(writer, "Main", cols=['Diff1', 'Diff2'])
  
  writer.save()
  </code></pre>
  
  <p>Masterfile.xlsx already consists of number of different tabs. However, it does not yet contain "Main".</p>
  
  <p>Pandas correctly writes to "Main" sheet, unfortunately it also deletes all other tabs.</p>