title: Pandas, skip empty columns in xslx
body: <p>Im trying to find if a .xlsx file contains a @.
  I have used pandas, which work great, unless if the excel sheet have the first column empty, then it fails.. any ideas how to rewrite the code to handle/skip empty columns?</p>
  
  <p>the code:</p>
  
  <pre><code>df = pandas.read_excel(open(path,'rb'), sheetname=0)
  out = 'False'
  for col in df.columns:
      if df[col].str.contains('@').any():
          out = 'True'
          break
  </code></pre>
  
  <p>This is the error i'm getting:</p>
  
  <pre><code>    df = pandas.read_excel(open(path,'rb'), sheetname=0)
    File "/anaconda3/lib/python3.6/site-packages/pandas/io/excel.py", line 203, in read_excel
      io = ExcelFile(io, engine=engine)
    File "/anaconda3/lib/python3.6/site-packages/pandas/io/excel.py", line 258, in __init__
      self.book = xlrd.open_workbook(file_contents=data)
    File "/anaconda3/lib/python3.6/site-packages/xlrd/__init__.py", line 162, in open_workbook
      ragged_rows=ragged_rows,
    File "/anaconda3/lib/python3.6/site-packages/xlrd/book.py", line 91, in open_workbook_xls
      biff_version = bk.getbof(XL_WORKBOOK_GLOBALS)
    File "/anaconda3/lib/python3.6/site-packages/xlrd/book.py", line 1271, in getbof
      bof_error('Expected BOF record; found %r' % self.mem[savpos:savpos+8])
    File "/anaconda3/lib/python3.6/site-packages/xlrd/book.py", line 1265, in bof_error
      raise XLRDError('Unsupported format, or corrupt file: ' + msg)
  xlrd.biffh.XLRDError: Unsupported format, or corrupt file: Expected BOF record; found b'\x17Microso'
  </code></pre>