Example 2: Working with R script - Teradata Vantage

In this example, the R script mapper.R reads in a line of text input ("Old Macdonald Had A Farm") from csv and splits the line into individual words, emitting a new row for each word.

• Create teradataml DataFrame object.

  >>> barrierdf = DataFrame.from_table("barrier")

• Create remote user environment.

  >>> testenv = create_env('test_env_for_r', 'r_4.1', 'Demo environment')
  User environment test_env_for_r created.

  >>> import os, teradataml

• Install file in remote user environment.

  >>> testenv.install_file(file_path=os.path.join(os.path.dirname(teradataml.__file__), "data", "scripts", "mapper.R"))
  File 'mapper.R' installed successfully in the remote user environment 'test_env_for_r'.

• Create an APPLY object that allows user to run script.

  >>> apply_obj = Apply(data=barrierdf,
                        apply_command='Rscript --vanilla mapper.R',
                        data_order_column="Id",
                        is_local_order=False,
                        nulls_first=False,
                        sort_ascending=False,
                        returns={"word": VARCHAR(15), "count_input": VARCHAR(10)},
                        env_name=testenv,
                        delimiter='\t')

• Run the user script in Open Analytics Framework

  >>> apply_obj.execute_script()
          word count_input
  0  Macdonald           1
  1          A           1
  2       Farm           1
  3        Had           1
  4        Old           1
  5          1           1

• Remove the installed file from remote user environment.

  >>> apply_obj.remove_file(file_name='mapper.R')
  File 'mapper.R' removed successfully from the remote user environment 'test_env_for_r'.