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Get RMSE

Now that you know how to build a model and generate predictions, and have an evaluator to tell us how well it predicts ratings, we can calculate the RMSE to see how well an ALS model performed. We'll use the evaluator that we built in the previous exercise to calculate and print the rmse.

This exercise is part of the course

Building Recommendation Engines with PySpark

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Exercise instructions

  • Call the .evaluate() method on our evaluator to calculate our RMSE on the test_predictions dataframe. Call the result RMSE.
  • Print the RMSE

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Evaluate the "test_predictions" dataframe
RMSE = evaluator.____(____)

# Print the RMSE
print (____)
Edit and Run Code