.. _pylab_examples-scatter_demo2:

pylab_examples example code: scatter_demo2.py
=============================================



.. plot:: /home/mdboom/Work/builds/matplotlib/doc/mpl_examples/pylab_examples/scatter_demo2.py

::

    """
    make a scatter plot with varying color and size arguments
    """
    import matplotlib
    import numpy as np
    import matplotlib.pyplot as plt
    import matplotlib.mlab as mlab
    import matplotlib.cbook as cbook
    
    # load a numpy record array from yahoo csv data with fields date,
    # open, close, volume, adj_close from the mpl-data/example directory.
    # The record array stores python datetime.date as an object array in
    # the date column
    datafile = cbook.get_sample_data('goog.npy')
    r = np.load(datafile).view(np.recarray)
    r = r[-250:] # get the most recent 250 trading days
    
    delta1 = np.diff(r.adj_close)/r.adj_close[:-1]
    
    # size in points ^2
    volume = (15*r.volume[:-2]/r.volume[0])**2
    close = 0.003*r.close[:-2]/0.003*r.open[:-2]
    
    fig = plt.figure()
    ax = fig.add_subplot(111)
    ax.scatter(delta1[:-1], delta1[1:], c=close, s=volume, alpha=0.75)
    
    #ticks = arange(-0.06, 0.061, 0.02)
    #xticks(ticks)
    #yticks(ticks)
    
    ax.set_xlabel(r'$\Delta_i$', fontsize=20)
    ax.set_ylabel(r'$\Delta_{i+1}$', fontsize=20)
    ax.set_title('Volume and percent change')
    ax.grid(True)
    
    plt.show()
    
    
    
    

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