title: Python remove stop words from pandas dataframe give wrong output
body: <p>I remove the stopword from multiple files. First I read each file and remove the stop word from the dataframe. After that I concatenate the dataframe with the next dataframe. When I print the dataframe it gives me an output like:</p>
  
  <pre><code>0      [I,  ,  ,  ,  , r, e,  , h,  , h,  , h, v, e, ...      
  1      [D,  , u,  , e, v, e, n,  , e,  , h, e,  , u, ...     
  2      [R, g, h,  , f, r,  , h, e,  , e, c, r,  , w, ...     
  3      [A, f, e, r,  , c, l, l, n, g,  , n,  , p, l, ...     
  4      [T, h, e, r, e,  , v, e, r, e, e, n,  ,  , n, ...   
  </code></pre>
  
  <p>Here is my code:</p>
  
  <pre><code>allFiles = glob.glob(ROOT_DIR + '/' + DATASET + "/*.csv")
  frame = pd.DataFrame()
  list_ = []
  stop = stopwords.words('english') 
  for file_ in allFiles:
      chunkDataframe = pd.read_csv(file_,index_col=None, header=0, chunksize=1000)
      dataframe = pd.concat(chunkDataframe, ignore_index=True)
      dataframe['Text'] = dataframe['Text'].apply(lambda x: [item for item in x if item not in stop])
      print dataframe
      list_.append(dataframe)
  frame = pd.concat(list_)
  </code></pre>
  
  <p>Please help me optimize the way to read multiple files with removed stop word from it.</p>