.. note::
    :class: sphx-glr-download-link-note

    Click :ref:`here <sphx_glr_download_auto_examples_exercises_plot_cv_digits.py>` to download the full example code or to run this example in your browser via Binder
.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_exercises_plot_cv_digits.py:


=============================================
Cross-validation on Digits Dataset Exercise
=============================================

A tutorial exercise using Cross-validation with an SVM on the Digits dataset.

This exercise is used in the :ref:`cv_generators_tut` part of the
:ref:`model_selection_tut` section of the :ref:`stat_learn_tut_index`.



.. image:: /auto_examples/exercises/images/sphx_glr_plot_cv_digits_001.png
    :class: sphx-glr-single-img






.. code-block:: default

    print(__doc__)


    import numpy as np
    from sklearn.model_selection import cross_val_score
    from sklearn import datasets, svm

    X, y = datasets.load_digits(return_X_y=True)

    svc = svm.SVC(kernel='linear')
    C_s = np.logspace(-10, 0, 10)

    scores = list()
    scores_std = list()
    for C in C_s:
        svc.C = C
        this_scores = cross_val_score(svc, X, y, n_jobs=1)
        scores.append(np.mean(this_scores))
        scores_std.append(np.std(this_scores))

    # Do the plotting
    import matplotlib.pyplot as plt
    plt.figure()
    plt.semilogx(C_s, scores)
    plt.semilogx(C_s, np.array(scores) + np.array(scores_std), 'b--')
    plt.semilogx(C_s, np.array(scores) - np.array(scores_std), 'b--')
    locs, labels = plt.yticks()
    plt.yticks(locs, list(map(lambda x: "%g" % x, locs)))
    plt.ylabel('CV score')
    plt.xlabel('Parameter C')
    plt.ylim(0, 1.1)
    plt.show()


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  8.988 seconds)

**Estimated memory usage:**  8 MB


.. _sphx_glr_download_auto_examples_exercises_plot_cv_digits.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example


  .. container:: binder-badge

    .. image:: https://mybinder.org/badge_logo.svg
      :target: https://mybinder.org/v2/gh/scikit-learn/scikit-learn/0.22.X?urlpath=lab/tree/notebooks/auto_examples/exercises/plot_cv_digits.ipynb
      :width: 150 px


  .. container:: sphx-glr-download

     :download:`Download Python source code: plot_cv_digits.py <plot_cv_digits.py>`



  .. container:: sphx-glr-download

     :download:`Download Jupyter notebook: plot_cv_digits.ipynb <plot_cv_digits.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_