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pythonscikit-learnpipelinegrid-search

Gridsearch in pipeline

I am searching over parameters in pipeline using GridSearchCV in Scikit. I made my code work, but if I want to add class_weights, I am hitting a wall.

from sklearn.pipeline import Pipeline

RFC = RandomForestClassifier()
PCA = PCA()
pipe = Pipeline(steps=[('PCA', PCA), ('RFC', RFC)])

param_dict = {'RFC__n_estimators': [100,150],
              'RFC__class_weights': [{0:1,1:2},{0:1,1:4}],
              'PCA__n_components': [60,80]}

from sklearn.grid_search import GridSearchCV             
estimator = GridSearchCV(pipe, param_dict, scoring='roc_auc')
estimator.fit(X_train, y_train)

What is the proper way how to add this parameter to GridSearch?

Solution

  • Simple - You've got the wrong parameter name:

    class_weight : dict, list of dicts, “balanced”, “balanced_subsample” or None, optional