.. _statistics-boxplot_vs_violin_demo:

statistics example code: boxplot_vs_violin_demo.py
==================================================



.. plot:: /home/tcaswell/src/p/matplotlib/doc/mpl_examples/statistics/boxplot_vs_violin_demo.py

::

    """
    ===================================
    Box plot vs. violin plot comparison
    ===================================
    
    Note that although violin plots are closely related to Tukey's (1977)
    box plots, they add useful information such as the distribution of the
    sample data (density trace).
    
    By default, box plots show data points outside 1.5 * the inter-quartile
    range as outliers above or below the whiskers whereas violin plots show
    the whole range of the data.
    
    A good general reference on boxplots and their history can be found
    here: http://vita.had.co.nz/papers/boxplots.pdf
    
    Violin plots require matplotlib >= 1.4.
    
    For more information on violin plots, the scikit-learn docs have a great
    section: http://scikit-learn.org/stable/modules/density.html
    """
    
    import matplotlib.pyplot as plt
    import numpy as np
    
    fig, axes = plt.subplots(nrows=1, ncols=2, figsize=(9, 4))
    
    # generate some random test data
    all_data = [np.random.normal(0, std, 100) for std in range(6, 10)]
    
    # plot violin plot
    axes[0].violinplot(all_data,
                       showmeans=False,
                       showmedians=True)
    axes[0].set_title('violin plot')
    
    # plot box plot
    axes[1].boxplot(all_data)
    axes[1].set_title('box plot')
    
    # adding horizontal grid lines
    for ax in axes:
        ax.yaxis.grid(True)
        ax.set_xticks([y+1 for y in range(len(all_data))])
        ax.set_xlabel('xlabel')
        ax.set_ylabel('ylabel')
    
    # add x-tick labels
    plt.setp(axes, xticks=[y+1 for y in range(len(all_data))],
             xticklabels=['x1', 'x2', 'x3', 'x4'])
    plt.show()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)