

.. _sphx_glr_gallery_animation_histogram.py:


==================
Animated histogram
==================

This example shows how to use a path patch to draw a bunch of
rectangles for an animated histogram.





.. image:: /gallery/animation/images/sphx_glr_histogram_001.png
    :align: center





.. code-block:: python

    import numpy as np

    import matplotlib.pyplot as plt
    import matplotlib.patches as patches
    import matplotlib.path as path
    import matplotlib.animation as animation

    fig, ax = plt.subplots()

    # Fixing random state for reproducibility
    np.random.seed(19680801)

    # histogram our data with numpy
    data = np.random.randn(1000)
    n, bins = np.histogram(data, 100)

    # get the corners of the rectangles for the histogram
    left = np.array(bins[:-1])
    right = np.array(bins[1:])
    bottom = np.zeros(len(left))
    top = bottom + n
    nrects = len(left)

    # here comes the tricky part -- we have to set up the vertex and path
    # codes arrays using moveto, lineto and closepoly

    # for each rect: 1 for the MOVETO, 3 for the LINETO, 1 for the
    # CLOSEPOLY; the vert for the closepoly is ignored but we still need
    # it to keep the codes aligned with the vertices
    nverts = nrects*(1 + 3 + 1)
    verts = np.zeros((nverts, 2))
    codes = np.ones(nverts, int) * path.Path.LINETO
    codes[0::5] = path.Path.MOVETO
    codes[4::5] = path.Path.CLOSEPOLY
    verts[0::5, 0] = left
    verts[0::5, 1] = bottom
    verts[1::5, 0] = left
    verts[1::5, 1] = top
    verts[2::5, 0] = right
    verts[2::5, 1] = top
    verts[3::5, 0] = right
    verts[3::5, 1] = bottom

    barpath = path.Path(verts, codes)
    patch = patches.PathPatch(
        barpath, facecolor='green', edgecolor='yellow', alpha=0.5)
    ax.add_patch(patch)

    ax.set_xlim(left[0], right[-1])
    ax.set_ylim(bottom.min(), top.max())


    def animate(i):
        # simulate new data coming in
        data = np.random.randn(1000)
        n, bins = np.histogram(data, 100)
        top = bottom + n
        verts[1::5, 1] = top
        verts[2::5, 1] = top
        return [patch, ]

    ani = animation.FuncAnimation(fig, animate, 100, repeat=False, blit=True)
    plt.show()

**Total running time of the script:** ( 0 minutes  0.085 seconds)



.. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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

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

    `Generated by Sphinx-Gallery <https://sphinx-gallery.readthedocs.io>`_
