.. _sphx_glr_gallery_statistics_histogram_features.py:


=========================================================
Demo of the histogram (hist) function with a few features
=========================================================

In addition to the basic histogram, this demo shows a few optional
features:

    * Setting the number of data bins
    * The ``normed`` flag, which normalizes bin heights so that the
      integral of the histogram is 1. The resulting histogram is an
      approximation of the probability density function.
    * Setting the face color of the bars
    * Setting the opacity (alpha value).

Selecting different bin counts and sizes can significantly affect the
shape of a histogram. The Astropy docs have a great section on how to
select these parameters:
http://docs.astropy.org/en/stable/visualization/histogram.html




.. image:: /gallery/statistics/images/sphx_glr_histogram_features_001.png
    :align: center





.. code-block:: python


    import numpy as np
    import matplotlib.pyplot as plt

    np.random.seed(19680801)

    # example data
    mu = 100  # mean of distribution
    sigma = 15  # standard deviation of distribution
    x = mu + sigma * np.random.randn(437)

    num_bins = 50

    fig, ax = plt.subplots()

    # the histogram of the data
    n, bins, patches = ax.hist(x, num_bins, density=1)

    # add a 'best fit' line
    y = ((1 / (np.sqrt(2 * np.pi) * sigma)) *
         np.exp(-0.5 * (1 / sigma * (bins - mu))**2))
    ax.plot(bins, y, '--')
    ax.set_xlabel('Smarts')
    ax.set_ylabel('Probability density')
    ax.set_title(r'Histogram of IQ: $\mu=100$, $\sigma=15$')

    # Tweak spacing to prevent clipping of ylabel
    fig.tight_layout()
    plt.show()



.. only :: html

 .. container:: sphx-glr-footer


  .. container:: sphx-glr-download

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



  .. container:: sphx-glr-download

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


.. only:: html

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

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