sklearn_compat_check_is_fitted_validation_quickstart.py

1from sklearn_compat.utils.validation import check_is_fitted
2from sklearn.linear_model import LogisticRegression
3import numpy as np
4
5# Create some sample data
6X = np.array([[1, 2], [3, 4]])
7y = np.array([0, 1])
8
9# Initialize a model
10clf = LogisticRegression()
11
12# Check if the model is fitted before training (should raise a NotFittedError)
13try:
14    check_is_fitted(clf)
15except Exception as e:
16    print(f"Before fit: {e}")
17
18# Fit the model
19clf.fit(X, y)
20
21# Check if the model is fitted after training (should pass silently)
22check_is_fitted(clf)
23print("After fit: Model is successfully fitted.")