3.4.8.9. Compare classifiers on the digits data

Compare the performance of a variety of classifiers on a test set for the digits data.

/opt/hostedtoolcache/Python/3.11.9/x64/lib/python3.11/site-packages/sklearn/svm/_classes.py:31: FutureWarning: The default value of `dual` will change from `True` to `'auto'` in 1.5. Set the value of `dual` explicitly to suppress the warning.
  warnings.warn(
/opt/hostedtoolcache/Python/3.11.9/x64/lib/python3.11/site-packages/sklearn/svm/_base.py:1237: ConvergenceWarning: Liblinear failed to converge, increase the number of iterations.
  warnings.warn(
LinearSVC: 0.9341800269333108
GaussianNB: 0.8332741681010102
KNeighborsClassifier: 0.9804562804949924
------------------
/opt/hostedtoolcache/Python/3.11.9/x64/lib/python3.11/site-packages/sklearn/svm/_classes.py:31: FutureWarning: The default value of `dual` will change from `True` to `'auto'` in 1.5. Set the value of `dual` explicitly to suppress the warning.
  warnings.warn(
/opt/hostedtoolcache/Python/3.11.9/x64/lib/python3.11/site-packages/sklearn/svm/_base.py:1237: ConvergenceWarning: Liblinear failed to converge, increase the number of iterations.
  warnings.warn(
LinearSVC(loss='hinge'): 0.9294570108037394
/opt/hostedtoolcache/Python/3.11.9/x64/lib/python3.11/site-packages/sklearn/svm/_classes.py:31: FutureWarning: The default value of `dual` will change from `True` to `'auto'` in 1.5. Set the value of `dual` explicitly to suppress the warning.
  warnings.warn(
/opt/hostedtoolcache/Python/3.11.9/x64/lib/python3.11/site-packages/sklearn/svm/_base.py:1237: ConvergenceWarning: Liblinear failed to converge, increase the number of iterations.
  warnings.warn(
LinearSVC(loss='squared_hinge'): 0.9341371852581549
-------------------
KNeighbors(n_neighbors=1): 0.9913675218842191
KNeighbors(n_neighbors=2): 0.9848442068835102
KNeighbors(n_neighbors=3): 0.9867753449543099
KNeighbors(n_neighbors=4): 0.9803719053818863
KNeighbors(n_neighbors=5): 0.9804562804949924
KNeighbors(n_neighbors=6): 0.9757924194139573
KNeighbors(n_neighbors=7): 0.9780645792142071
KNeighbors(n_neighbors=8): 0.9780645792142071
KNeighbors(n_neighbors=9): 0.9780645792142071
KNeighbors(n_neighbors=10): 0.9755550897728812

from sklearn import model_selection, datasets, metrics
from sklearn.svm import LinearSVC
from sklearn.naive_bayes import GaussianNB
from sklearn.neighbors import KNeighborsClassifier

digits = datasets.load_digits()
X = digits.data
y = digits.target
X_train, X_test, y_train, y_test = model_selection.train_test_split(
    X, y, test_size=0.25, random_state=0
)

for Model in [LinearSVC, GaussianNB, KNeighborsClassifier]:
    clf = Model().fit(X_train, y_train)
    y_pred = clf.predict(X_test)
    print(f"{Model.__name__}: {metrics.f1_score(y_test, y_pred, average='macro')}")

print("------------------")

# test SVC loss
for loss in ["hinge", "squared_hinge"]:
    clf = LinearSVC(loss=loss).fit(X_train, y_train)
    y_pred = clf.predict(X_test)
    print(
        f"LinearSVC(loss='{loss}'): {metrics.f1_score(y_test, y_pred, average='macro')}"
    )

print("-------------------")

# test the number of neighbors
for n_neighbors in range(1, 11):
    clf = KNeighborsClassifier(n_neighbors=n_neighbors).fit(X_train, y_train)
    y_pred = clf.predict(X_test)
    print(
        f"KNeighbors(n_neighbors={n_neighbors}): {metrics.f1_score(y_test, y_pred, average='macro')}"
    )