title: How to increase process speed using read_excel in pandas?
body: <p>I need use <em>pd.read_excel</em> to process every sheet in one excel file.<br>
  But in most cases,I did not know the sheet name.<br>
  So I use this to judge how many sheet in excel:    </p>
  
  <pre><code>i_sheet_count=0
  i=0
  try:
    df.read_excel('/tmp/1.xlsx',sheetname=i)
    i_sheet_count+=1
    i+=1
  else:
    i+=1
  print(i_sheet_count)
  </code></pre>
  
  <p>During the process,I found  that the process is quite slow,<br>
  So,can <em>read_excel</em> only read limited rows to improve the speed?<br>
  I tried <em>nrows</em> but did not work..still slow..</p>