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Vowpal Wabbit basics with Python

This tutorial is a quick introduction to training and testing your model with Vowpal Wabbit using Python. We explore passing some data to Vowpal Wabbit to learn a model and get a prediction.

For more advanced Vowpal Wabbit tutorials, including how to format data and understand results, see Tutorials.

Prerequisites

To install Vowpal Wabbit see Get Started.

Getting started

First, import the Vowpal Wabbit Python package for this tutorial:

from vowpalwabbit import pyvw

Next, we create an instance of Vowpal Wabbit, and pass the quiet=True option to avoid diagnostic information output to stdout location:

model = pyvw.vw(quiet=True)

Training scenario and dataset

For this tutorial scenario, we want Vowpal Wabbit to help us predict whether or not our house will require a new roof in the next 10 years.

To create some examples, we use the Vowpal Wabbit text format and then learn on them:

train_examples = [
  "0 | price:.23 sqft:.25 age:.05 2006",
  "1 | price:.18 sqft:.15 age:.35 1976",
  "0 | price:.53 sqft:.32 age:.87 1924",
]

for example in train_examples:
    model.learn(example)

Note: For more details on Vowpal Wabbit input format and feature hashing techniques see the Linear Regression Tutorial.

Now, we create a test_example to use for prediction:

test_example = "| price:.46 sqft:.4 age:.10 1924"

prediction = model.predict(test_example)
print(prediction)

Output:

0.0

Vowpal Wabbit results

The model predicted a value of 0. According to our learning model, our house will not need a new roof in the next 10 years (at least that is the result from just three examples we used in our training dataset).

More to explore

  • To learn how to approach a contextual bandits problem using Vowpal Wabbit — including how to work with different contextual bandits approaches, how to format data, and understand the results — see the Contextual Bandit Reinforcement Learning Tutorial.
  • For more on the contextual bandits approach to reinforcement learning, including a content personalization scenario, see the Contextual Bandit Simulation Tutorial.
  • See the Linear Regression Tutorial for a different look at the roof replacement problem and learn more about Vowpal Wabbit’s format and understanding the results.

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