CatBoost - Data Preprocessing

CatBoost data preprocessing involves handling of categorical features and minimizing memory usage in order to prepare data for training. Categorical variables may not need any manual preprocessing processes just like one-hot encoding, as they can be handled automatically. CatBoost increases data preparation by allowing it to operate directly with missing values.

Data handling for training and prediction is made simpler and better by using a CatBoost pool that provides the dataset with features, labels, and categorical feature index. CatBoost simplifies the machine learning workflow by maintaining high prediction performance and reducing data preprocessing. So it allows users to focus more on model construction and optimization.

Why Data Preprocessing in CatBoost?

CatBoost simplifies data preprocessing for the below reasons −

• CatBoost can work directly with categorical features without the need for manual encoding. Just like one-hot encoding. This property saves time and minimize the complexity of the model.

• The catboost technique is used to handle missing values automatically which can save you to make an effort of putting them in before the model is trained.

• CatBoost may not ask you to scale your features in the same manner that normalization or classification does unlike other boosting methods. This tool makes preprocessing very easy.

• By using different data sections in training, CatBoost provides methods that reduce over-fitting.

• Preprocessing can be used to manage large datasets with a lot of features.

• The CatBoost library was created to be easy to use with clear documentation and basic APIs. Because of this functionality both experts and beginners can use it.

Steps for Preprocessing

Here are a simple steps of data preprocessing for CatBoost −

• Step 1: Install CatBoost: First you need to make sure that you have CatBoost installed. You can install it by using the below command:

  pip install catboost
  

• Step 2: Prepare Your Data − Now you have to prepare your data and your data should be in a structured format, like a pandas DataFrame.

• Step 3: Identify Categorical Features − Now list the columns that are categorical. So that the CatBoost library can automatically handle them, but you should specify them.

• Step 4: Encode Categorical Features − You do not need to manually encode categorical features because CatBoost can take them automatically. But be careful while defining which feature is categorical.

• Step 5: Split Your Data −Then you can divide your data into the training and testing sets. This process will help you to evaluate the model in next stages.

  from sklearn.model_selection import train_test_split
  X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)
  

• Step 6: Create a Pool − CatBoost makes use of a special data structure which is called a 'Pool' for training. You can create it like the below:

  from catboost import Pool
  
  train_pool = Pool(X_train, y_train, cat_features=categorical_features)
  test_pool = Pool(X_test, y_test, cat_features=categorical_features)
  

• Step 7: Train the Model − Now with the help of your prepared data, you can train the model:

  from catboost import CatBoostClassifier
  
  model = CatBoostClassifier(iterations=1000, learning_rate=0.1, depth=6)
  model.fit(train_pool)
  

• Step 8: Make Predictions − Predictions can be done by using the model to the test set::

  predictions = model.predict(test_pool)
  

• Step 9: Evaluate the Model − Finally, you can use measures like accuracy or F1 score to evaluate the way your model performs.