Recursive feature elimination#

This example demonstrates how Recursive Feature Elimination (RFE) can be used to determine the importance of individual pixels for classifying handwritten digits. RFE recursively removes the least significant features, assigning ranks based on their importance, where higher ranking_ values denote lower importance. The ranking is visualized using both shades of blue and pixel annotations for clarity. As expected, pixels positioned at the center of the image tend to be more predictive than those near the edges.

Ranking of pixels with RFE (Logistic Regression)
import matplotlib.pyplot as plt

from sklearn.datasets import load_digits
from sklearn.feature_selection import RFE
from sklearn.linear_model import LogisticRegression
from sklearn.pipeline import Pipeline
from sklearn.preprocessing import MinMaxScaler

# Load the digits dataset
digits = load_digits()
X = digits.images.reshape((len(digits.images), -1))
y = digits.target

pipe = Pipeline(
    [
        ("scaler", MinMaxScaler()),
        ("rfe", RFE(estimator=LogisticRegression(), n_features_to_select=1, step=1)),
    ]
)

pipe.fit(X, y)
ranking = pipe.named_steps["rfe"].ranking_.reshape(digits.images[0].shape)

# Plot pixel ranking
plt.matshow(ranking, cmap=plt.cm.Blues)

# Add annotations for pixel numbers
for i in range(ranking.shape[0]):
    for j in range(ranking.shape[1]):
        plt.text(j, i, str(ranking[i, j]), ha="center", va="center", color="black")

plt.colorbar()
plt.title("Ranking of pixels with RFE\n(Logistic Regression)")
plt.show()

Total running time of the script: (0 minutes 3.098 seconds)

Related examples

Recognizing hand-written digits

Recognizing hand-written digits

The Digit Dataset

The Digit Dataset

Kernel Density Estimation

Kernel Density Estimation

Feature agglomeration

Feature agglomeration

Gallery generated by Sphinx-Gallery