title: Python: TypeError: unhashable type: 'slice'
body: <p>I am reading CSV using python, here is the code.</p>
  
  <pre><code>train_csv = open('train.csv')
  test_csv = open('test.csv')
  train_data_reader = csv.DictReader(train_csv)
  test_data_reader = csv.DictReader(test_csv)
  
  row=[]
  for row in train_data_reader:
      X.append([int(item) for item in row[4:]]) 
      char = row[1]
      Y.append(charIntConversion(char))
      train_id.append(row[0])
      prediction.append(row[1])
  for row in test_data_reader:
      test_id.append(row[0])
      test_X.append([int(item) for item in row[4:]]
  </code></pre>
  
  <p>when I tried to run the code, it shows that TypeError: unhashable type: 'slice' for</p>
  
  <pre><code>X.append([int(item) for item in row[4:]])
  test_X.append([int(item) for item in row[4:]] 
  </code></pre>
  
  <p>X and test_X should contain the value from column 4 to last column of the CSV.</p>
  
  <p>May I know what's wrong with my code and how can I fix this issue? </p>