title: Unicode DecodeError while concatenating
body: <p>I am trying to train my model and i have csv file and one gz file, which was generated earlier. I am getting this error as mentioned below and not sure what is wrong. </p>
  
  <pre><code>Traceback (most recent call last):
    File "Model.py", line 87, in &lt;module&gt;
      data = pd.concat([pd.read_csv(log)])
    File "/usr/local/lib/python3.6/site-packages/pandas/io/parsers.py", line 678, in parser_f
      return _read(filepath_or_buffer, kwds)
    File "/usr/local/lib/python3.6/site-packages/pandas/io/parsers.py", line 440, in _read
      parser = TextFileReader(filepath_or_buffer, **kwds)
    File "/usr/local/lib/python3.6/site-packages/pandas/io/parsers.py", line 787, in __init__
      self._make_engine(self.engine)
    File "/usr/local/lib/python3.6/site-packages/pandas/io/parsers.py", line 1014, in _make_engine
      self._engine = CParserWrapper(self.f, **self.options)
    File "/usr/local/lib/python3.6/site-packages/pandas/io/parsers.py", line 1708, in __init__
      self._reader = parsers.TextReader(src, **kwds)
    File "pandas/_libs/parsers.pyx", line 539, in pandas._libs.parsers.TextReader.__cinit__
    File "pandas/_libs/parsers.pyx", line 767, in pandas._libs.parsers.TextReader._get_header
  UnicodeDecodeError: 'utf-8' codec can't decode byte 0x8b in position 1: invalid start byte
  </code></pre>
  
  <p>Mycode:</p>
  
  <pre><code>for foo in range(0,1):
      # Read dataframe
      #data = pd.concat([pd.read_csv(log.replace('0',str(idx),1)) for idx in range(5)])
      log = path + 'train_features/log_.csv'
  
      test_log = path + 'test_features/log_features.gz'
      data = pd.concat([pd.read_csv(log)])
  </code></pre>