title: pySpark Data Frames "assert isinstance(dataType, DataType), "dataType should be DataType"
body: <p>I want to generate my Data Frame schema dynamically I have the following 
  Error:</p>
  
  <pre><code>   assert isinstance(dataType, DataType), "dataType should be DataType"
  AssertionError: dataType should be DataType
  </code></pre>
  
  <p>code:</p>
  
  <pre><code>filteredSchema = []
  for line in correctSchema:
      fieldName = line.split(',')
      if fieldName[1] == "decimal":
          filteredSchema.append([fieldName[0], "DecimalType()"])
      elif fieldName[1] == "string":
          filteredSchema.append([fieldName[0], "StringType()"])
      elif fieldName[1] == "integer":
          filteredSchema.append([fieldName[0], "IntegerType()"])
      elif fieldName[1] == "date":
          filteredSchema.append([fieldName[0], "DateType()"])
  
  
  sample1 = [(line[0], line[1], True) for line in filteredSchema]
  print sample1
  
  fields = [StructField(line[0], line[1], True) for line in filteredSchema]
  </code></pre>
  
  <p>If I use this:</p>
  
  <pre><code>fields = [StructField(line[0], StringType(), True) for line in filteredSchema]
  </code></pre>
  
  <p>It works,</p>
  
  <p>but the print out of sample1 is:</p>
  
  <pre><code>[('record_id', 'StringType()', True), ('offer_id', 'DecimalType()', True), ('decision_id', 'DecimalType()', True), ('offer_type_cd', 'DecimalType()', True), ('promo_id', 'DecimalType()', True), ('pymt_method_type_cd', 'DecimalType()', True), ('cs_result_id', 'DecimalType()', True), ('cs_result_usage_type_cd', 'DecimalType()', True), ('rate_index_type_cd', 'DecimalType()', True), ('sub_product_id', 'DecimalType()', True), ('campaign_id', 'DecimalType()', True), ('market_cell_id', 'DecimalType()', True), ('assigned_offer_id', 'StringType()', True), ('accepted_offer_flag', 'StringType()', True), ('current_offer_flag', 'StringType()', True), ('offer_good_until_date', 'StringType()', True), ('rescindable_days', 'DecimalType()', True), ('rescinded_date', 'StringType()', True), ('amount', 'DecimalType()', True), ('max_amount', 'DecimalType()', True), ('amount_financed', 'DecimalType()', True), ('down_pymt', 'DecimalType()', True), ('rate', 'DecimalType()', True), ('term_mm', 'DecimalType()', True), ('origination_fee_amount', 'DecimalType()', True), ('origination_fee_rate', 'DecimalType()', True), ('finance_charge', 'DecimalType()', True), ('nbr_of_pymts', 'DecimalType()', True), ('pymt', 'DecimalType()', True), ('total_pymts', 'DecimalType()', True), ('first_pymt_date', 'StringType()', True), ('contract_date', 'StringType()', True), ('acct_nbr', 'StringType()', True), ('acct_nbr_assigned_dttm', 'StringType()', True), ('acct_expiration_dttm', 'StringType()', True), ('offer_desc', 'StringType()', True), ('min_rate', 'DecimalType()', True), ('max_rate', 'DecimalType()', True), ('min_amount', 'DecimalType()', True), ('annual_fee_amount', 'DecimalType()', True), ('annual_fee_waived_mm', 'DecimalType()', True), ('late_fee_percent', 'DecimalType()', True), ('late_fee_min_amount', 'DecimalType()', True), ('offer_sales_script', 'StringType()', True), ('offer_order', 'DecimalType()', True), ('presentable_flag', 'StringType()', True), ('index_rate', 'DecimalType()', True), ('insrt_dttm', 'StringType()', True), ('insrt_usr_id', 'StringType()', True), ('chng_dttm', 'StringType()', True), ('chng_usr_id', 'StringType()', True), ('actv_flag', 'StringType()', True), ('correlation_id', 'StringType()', True), ('offer_status_type_cd', 'StringType()', True), ('presentation_instrument_nbr', 'StringType()', True)]
  </code></pre>
  
  <p>I've tried just the DataType without (), also instead of DecimalType i've used FloatType().</p>