[Python] Lenght of features is not equal to the length of SHAP Values

Discussão em 'Python' iniciado por Stack, Março 17, 2025.

  1. Stack

    Stack Membro Participativo

    Im running a random forest model and to get some feature importance and Im trying to run a SHAP analysis. The problem is that every time I try to plot the shap values, I keep getting this error:

    DimensionError: Length of features is not equal to the length of shap_values.


    I don't know whats going on. When I run my XGBoost model, everything seems to go fine, i can see the SHAP plot for the data set. Its the exact same data set but it just wont run with random forest. Its for a binary classification.

    Here is my python code:

    from sklearn.ensemble import RandomForestClassifier
    from sklearn.model_selection import train_test_split, cross_val_score
    from sklearn.metrics import accuracy_score, precision_score, recall_score, f1_score, confusion_matrix

    # Remove the primary key column 'id' from the features

    features = result.drop(columns=['PQ2', 'id']) # Drop target and ID columns
    target = result['PQ2'] # Target variable

    # Split data into training and testing sets with 80-20 ratio
    X_train, X_test, y_train, y_test = train_test_split(features, target, test_size=0.2, random_state=42)

    # Initialize Random Forest classifier
    rf_model = RandomForestClassifier(n_estimators=100, random_state=42)

    # Fit the model on the training data
    rf_model.fit(X_train, y_train)

    # Make predictions
    y_pred = rf_model.predict(X_test)

    import shap

    # Create a Tree SHAP explainer for the Random Forest model
    explainer = shap.TreeExplainer(rf_model)

    # Calculate SHAP values for the test set
    shap_values = explainer.shap_values(X_test)

    # Plot a SHAP summary plot
    shap.summary_plot(shap_values, X_test, feature_names=features_names)

    # Plot a SHAP bar plot for global feature importance

    shap.summary_plot(shap_values, X_test, feature_names=features_names, plot_type="bar")


    The shape of test set is (829,22), yet the SHAP values consistently return (22,2) for random forest and I dont know how to fix it. The data set has been preprocessed, columns are either 0-1s or numerical columns.

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