title: Append existing excel sheet with new dataframe using python pandas
body: <p>I currently have this code. It works perfectly.</p>
  
  <p>It loops through excel files in a folder,
  removes the first 2 rows, then saves them as individual excel files,
  and it also saves the files in the loop as an appended file.</p>
  
  <p>Currently the appended file <strong>overwrites</strong> the existing file each time I run the code.</p>
  
  <p>I need to append the new data to the bottom of the <strong>already existing excel sheet</strong> ('master_data.xlsx)</p>
  
  <pre><code>dfList = []
  path = 'C:\\Test\\TestRawFile' 
  newpath = 'C:\\Path\\To\\New\\Folder'
  
  for fn in os.listdir(path): 
    # Absolute file path
    file = os.path.join(path, fn)
    if os.path.isfile(file): 
      # Import the excel file and call it xlsx_file 
      xlsx_file = pd.ExcelFile(file) 
      # View the excel files sheet names 
      xlsx_file.sheet_names 
      # Load the xlsx files Data sheet as a dataframe 
      df = xlsx_file.parse('Sheet1',header= None) 
      df_NoHeader = df[2:] 
      data = df_NoHeader 
      # Save individual dataframe
      data.to_excel(os.path.join(newpath, fn))
  
      dfList.append(data) 
  
  appended_data = pd.concat(dfList)
  appended_data.to_excel(os.path.join(newpath, 'master_data.xlsx'))
  </code></pre>
  
  <p>I thought this would be a simple task, but I guess not.
  I think I need to bring in the master_data.xlsx file as a dataframe, then match the index up with the new appended data, and save it back out. Or maybe there is an easier way. Any Help is appreciated.</p>