.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/prog/plot_pandas_groupby.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

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

        :ref:`Go to the end <sphx_glr_download_auto_examples_prog_plot_pandas_groupby.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_prog_plot_pandas_groupby.py:


=================
Pandas et groupby
=================

Petit tour de passe passe autour d'un :meth:`pandas.DataFrame.groupby`
et des valeurs manquantes qui ne sont plus prises en compte
depuis les dernières versions.

groupby et valeur manquantes
============================

.. GENERATED FROM PYTHON SOURCE LINES 14-24

.. code-block:: Python



    import pandas


    data = [{"a": 1, "b": 2}, {"a": 10, "b": 20}, {"b": 3}, {"b": 4}]
    df = pandas.DataFrame(data)
    df







.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    <div>
    <style scoped>
        .dataframe tbody tr th:only-of-type {
            vertical-align: middle;
        }

        .dataframe tbody tr th {
            vertical-align: top;
        }

        .dataframe thead th {
            text-align: right;
        }
    </style>
    <table border="1" class="dataframe">
      <thead>
        <tr style="text-align: right;">
          <th></th>
          <th>a</th>
          <th>b</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th>0</th>
          <td>1.0</td>
          <td>2</td>
        </tr>
        <tr>
          <th>1</th>
          <td>10.0</td>
          <td>20</td>
        </tr>
        <tr>
          <th>2</th>
          <td>NaN</td>
          <td>3</td>
        </tr>
        <tr>
          <th>3</th>
          <td>NaN</td>
          <td>4</td>
        </tr>
      </tbody>
    </table>
    </div>
    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 26-30

.. code-block:: Python


    df.groupby("a").sum()







.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    <div>
    <style scoped>
        .dataframe tbody tr th:only-of-type {
            vertical-align: middle;
        }

        .dataframe tbody tr th {
            vertical-align: top;
        }

        .dataframe thead th {
            text-align: right;
        }
    </style>
    <table border="1" class="dataframe">
      <thead>
        <tr style="text-align: right;">
          <th></th>
          <th>b</th>
        </tr>
        <tr>
          <th>a</th>
          <th></th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th>1.0</th>
          <td>2</td>
        </tr>
        <tr>
          <th>10.0</th>
          <td>20</td>
        </tr>
      </tbody>
    </table>
    </div>
    </div>
    <br />
    <br />

.. GENERATED FROM PYTHON SOURCE LINES 31-33

Les valeurs manquantes ont disparu et c'est le comportement attendu
Il est possible de corriger le tir avec l'argument `dropna`.

.. GENERATED FROM PYTHON SOURCE LINES 33-36

.. code-block:: Python



    df.groupby("a", dropna=False).sum()





.. raw:: html

    <div class="output_subarea output_html rendered_html output_result">
    <div>
    <style scoped>
        .dataframe tbody tr th:only-of-type {
            vertical-align: middle;
        }

        .dataframe tbody tr th {
            vertical-align: top;
        }

        .dataframe thead th {
            text-align: right;
        }
    </style>
    <table border="1" class="dataframe">
      <thead>
        <tr style="text-align: right;">
          <th></th>
          <th>b</th>
        </tr>
        <tr>
          <th>a</th>
          <th></th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <th>1.0</th>
          <td>2</td>
        </tr>
        <tr>
          <th>10.0</th>
          <td>20</td>
        </tr>
        <tr>
          <th>NaN</th>
          <td>7</td>
        </tr>
      </tbody>
    </table>
    </div>
    </div>
    <br />
    <br />


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

   **Total running time of the script:** (0 minutes 0.026 seconds)


.. _sphx_glr_download_auto_examples_prog_plot_pandas_groupby.py:

.. only:: html

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

    .. container:: sphx-glr-download sphx-glr-download-jupyter

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

    .. container:: sphx-glr-download sphx-glr-download-python

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

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_pandas_groupby.zip <plot_pandas_groupby.zip>`


.. only:: html

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

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