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

.. only:: html

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

        Click :ref:`here <sphx_glr_download_gallery_statistics_barchart_demo.py>`
        to download the full example code

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

.. _sphx_glr_gallery_statistics_barchart_demo.py:


===================================
Percentiles as horizontal bar chart
===================================

Bar charts are useful for visualizing counts, or summary statistics
with error bars. Also see the :doc:`/gallery/lines_bars_and_markers/barchart`
or the :doc:`/gallery/lines_bars_and_markers/barh` example for simpler versions
of those features.

This example comes from an application in which grade school gym
teachers wanted to be able to show parents how their child did across
a handful of fitness tests, and importantly, relative to how other
children did. To extract the plotting code for demo purposes, we'll
just make up some data for little Johnny Doe.

.. GENERATED FROM PYTHON SOURCE LINES 17-162

.. code-block:: default


    import numpy as np
    import matplotlib
    import matplotlib.pyplot as plt
    from matplotlib.ticker import MaxNLocator
    from collections import namedtuple

    np.random.seed(42)

    Student = namedtuple('Student', ['name', 'grade', 'gender'])
    Score = namedtuple('Score', ['score', 'percentile'])

    # GLOBAL CONSTANTS
    test_names = ['Pacer Test', 'Flexed Arm\n Hang', 'Mile Run', 'Agility',
                  'Push Ups']
    test_units = dict(zip(test_names, ['laps', 'sec', 'min:sec', 'sec', '']))


    def attach_ordinal(num):
        """Convert an integer to an ordinal string, e.g. 2 -> '2nd'."""
        suffixes = {str(i): v
                    for i, v in enumerate(['th', 'st', 'nd', 'rd', 'th',
                                           'th', 'th', 'th', 'th', 'th'])}
        v = str(num)
        # special case early teens
        if v in {'11', '12', '13'}:
            return v + 'th'
        return v + suffixes[v[-1]]


    def format_score(score, test):
        """
        Create score labels for the right y-axis as the test name followed by the
        measurement unit (if any), split over two lines.
        """
        unit = test_units[test]
        if unit:
            return f'{score}\n{unit}'
        else:  # If no unit, don't include a newline, so that label stays centered.
            return score


    def format_ycursor(y):
        y = int(y)
        if y < 0 or y >= len(test_names):
            return ''
        else:
            return test_names[y]


    def plot_student_results(student, scores, cohort_size):
        fig, ax1 = plt.subplots(figsize=(9, 7))  # Create the figure
        fig.subplots_adjust(left=0.115, right=0.88)
        fig.canvas.set_window_title('Eldorado K-8 Fitness Chart')

        pos = np.arange(len(test_names))

        rects = ax1.barh(pos, [scores[k].percentile for k in test_names],
                         align='center',
                         height=0.5,
                         tick_label=test_names)

        ax1.set_title(student.name)

        ax1.set_xlim([0, 100])
        ax1.xaxis.set_major_locator(MaxNLocator(11))
        ax1.xaxis.grid(True, linestyle='--', which='major',
                       color='grey', alpha=.25)

        # Plot a solid vertical gridline to highlight the median position
        ax1.axvline(50, color='grey', alpha=0.25)

        # Set the right-hand Y-axis ticks and labels
        ax2 = ax1.twinx()

        # Set the tick locations
        ax2.set_yticks(pos)
        # Set equal limits on both yaxis so that the ticks line up
        ax2.set_ylim(ax1.get_ylim())

        # Set the tick labels
        ax2.set_yticklabels([format_score(scores[k].score, k) for k in test_names])

        ax2.set_ylabel('Test Scores')

        xlabel = ('Percentile Ranking Across {grade} Grade {gender}s\n'
                  'Cohort Size: {cohort_size}')
        ax1.set_xlabel(xlabel.format(grade=attach_ordinal(student.grade),
                                     gender=student.gender.title(),
                                     cohort_size=cohort_size))

        rect_labels = []
        # Lastly, write in the ranking inside each bar to aid in interpretation
        for rect in rects:
            # Rectangle widths are already integer-valued but are floating
            # type, so it helps to remove the trailing decimal point and 0 by
            # converting width to int type
            width = int(rect.get_width())

            rank_str = attach_ordinal(width)
            # The bars aren't wide enough to print the ranking inside
            if width < 40:
                # Shift the text to the right side of the right edge
                xloc = 5
                # Black against white background
                clr = 'black'
                align = 'left'
            else:
                # Shift the text to the left side of the right edge
                xloc = -5
                # White on magenta
                clr = 'white'
                align = 'right'

            # Center the text vertically in the bar
            yloc = rect.get_y() + rect.get_height() / 2
            label = ax1.annotate(
                rank_str, xy=(width, yloc), xytext=(xloc, 0),
                textcoords="offset points",
                horizontalalignment=align, verticalalignment='center',
                color=clr, weight='bold', clip_on=True)
            rect_labels.append(label)

        # Make the interactive mouse over give the bar title
        ax2.fmt_ydata = format_ycursor
        # Return all of the artists created
        return {'fig': fig,
                'ax': ax1,
                'ax_right': ax2,
                'bars': rects,
                'perc_labels': rect_labels}


    student = Student('Johnny Doe', 2, 'boy')
    scores = dict(zip(
        test_names,
        (Score(v, p) for v, p in
         zip(['7', '48', '12:52', '17', '14'],
             np.round(np.random.uniform(0, 100, len(test_names)), 0)))))
    cohort_size = 62  # The number of other 2nd grade boys

    arts = plot_student_results(student, scores, cohort_size)
    plt.show()





.. image:: /gallery/statistics/images/sphx_glr_barchart_demo_001.png
    :alt: Johnny Doe
    :class: sphx-glr-single-img





.. GENERATED FROM PYTHON SOURCE LINES 163-170

------------

References
""""""""""

The use of the following functions, methods and classes is shown
in this example:

.. GENERATED FROM PYTHON SOURCE LINES 171-177

.. code-block:: default


    matplotlib.axes.Axes.bar
    matplotlib.pyplot.bar
    matplotlib.axes.Axes.annotate
    matplotlib.pyplot.annotate
    matplotlib.axes.Axes.twinx




.. rst-class:: sphx-glr-script-out

 Out:

 .. code-block:: none


    <function _AxesBase.twinx at 0x7f73be8e13a0>




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

   **Total running time of the script:** ( 0 minutes  1.247 seconds)


.. _sphx_glr_download_gallery_statistics_barchart_demo.py:


.. only :: html

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



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

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



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

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


.. only:: html

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

    Keywords: matplotlib code example, codex, python plot, pyplot
    `Gallery generated by Sphinx-Gallery
    <https://sphinx-gallery.readthedocs.io>`_
