Classification report with nested cross-validation in SKlearn (average / individual values)

Question

Can I get a classification report from cross_val_score through some workarounds? I use nested cross-validation and I can get various estimates here for the model, however I would like to see an external loop classification report. Any recommendations?

# Choose cross-validation techniques for the inner and outer loops,
# independently of the dataset.
# E.g "LabelKFold", "LeaveOneOut", "LeaveOneLabelOut", etc.
inner_cv = KFold(n_splits=4, shuffle=True, random_state=i)
outer_cv = KFold(n_splits=4, shuffle=True, random_state=i)

# Non_nested parameter search and scoring
clf = GridSearchCV(estimator=svr, param_grid=p_grid, cv=inner_cv)

# Nested CV with parameter optimization
nested_score = cross_val_score(clf, X=X_iris, y=y_iris, cv=outer_cv)

I would like to see a classification report here along with rating values. http://scikit-learn.org/stable/modules/generated/sklearn.metrics.classification_report.html

Answer 1

, :

from sklearn.metrics import classification_report, accuracy_score, make_scorer

def classification_report_with_accuracy_score(y_true, y_pred):

    print classification_report(y_true, y_pred) # print classification report
    return accuracy_score(y_true, y_pred) # return accuracy score

cross_val_score , make_scorer:

# Nested CV with parameter optimization
nested_score = cross_val_score(clf, X=X_iris, y=y_iris, cv=outer_cv, \
               scoring=make_scorer(classification_report_with_accuracy_score))
print nested_score 

, nested_score .

http://scikit-learn.org/stable/auto_examples/model_selection/plot_nested_cross_validation_iris.html , :

#   precision    recall  f1-score   support    
#0       1.00      1.00      1.00        14
#1       1.00      1.00      1.00        14
#2       1.00      1.00      1.00         9

#avg / total       1.00      1.00      1.00        37

#[ 0.94736842  1.          0.97297297  1. ]

#Average difference of 0.007742 with std. dev. of 0.007688.

Answer 2

Sandipan, . , :

# Variables for average classification report
originalclass = []
predictedclass = []

#Make our customer score
def classification_report_with_accuracy_score(y_true, y_pred):
    originalclass.extend(y_true)
    predictedclass.extend(y_pred)
    return accuracy_score(y_true, y_pred) # return accuracy score

inner_cv = StratifiedKFold(n_splits=5, shuffle=True, random_state=i)
outer_cv = StratifiedKFold(n_splits=5, shuffle=True, random_state=i)

# Non_nested parameter search and scoring
clf = GridSearchCV(estimator=svr, param_grid=p_grid, cv=inner_cv)

# Nested CV with parameter optimization
nested_score = cross_val_score(clf, X=X_iris, y=y_iris, cv=outer_cv, scoring=make_scorer(classification_report_with_accuracy_score))

# Average values in classification report for all folds in a K-fold Cross-validation  
print(classification_report(originalclass, predictedclass)) 

Sandipan :

            precision    recall  f1-score   support

          0       1.00      1.00      1.00        50
          1       0.96      0.94      0.95        50
          2       0.94      0.96      0.95        50

avg / total       0.97      0.97      0.97       150