title: U-SQL Python extension DataFrame Column Format
body: <p>I am trying to use the Python Extension to run some code, but when I try to reference columns in the pandas dataframe, it says it cannot find the column:</p>
  
  <pre><code>if "hist_future_flag" not in [x.lower() for x in dfBLData.columns.values.tolist()]:
              ProcessSuccessFlag = False
              print('dfBLData (Input DataFrame) requires "hist_future_flag" column. Cols in dfBLData are: ')
              print(', '.join(dfBLData.columns.values.tolist()))
  </code></pre>
  
  <blockquote>
    <p>dfBLData (Input DataFrame) requires ""hist_future_flag"" column. Cols in dfBLData are: 
    b'geography', b'mitm_key', b'target', b'dow', b'time_key', b'hist_future_flag' ... [and so on]</p>
  </blockquote>
  
  <p>So it looks like they are coming in as bytes, but when I try to convert the headers, python says they are strings and cannot be decoded!</p>
  
  <p>Here is the relevant U-SQL I'm running:</p>
  
  <pre><code>@d = 
  SELECT [geography], [mitm_key], [target], [dow], [time_key],[hist_future_flag]
  FROM modeling.dbo.LandingZone
  WHERE geography == 5;
  
  @bl =
  REDUCE @d
  ON geography, mitm_key
  PRODUCE 
  time_key DateTime,
  predict float,
  hist_future_flag int
  USING new Extension.Python.Reducer(pyScript:@myScript);
  
  OUTPUT @bl
  TO "/test_reducer.csv"
  USING Outputters.Csv(outputHeader: true);
  </code></pre>