>>> """
=============
Scatter Demo2
=============

Demo of scatter plot with varying marker colors and sizes.
"""
... import numpy as np
... import matplotlib.pyplot as plt
... 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 the date as an np.datetime64 with a day unit ('D') in the date column.
... price_data = (cbook.get_sample_data('goog.npz', np_load=True)['price_data']
...               .view(np.recarray))
... price_data = price_data[-250:]  # get the most recent 250 trading days
... 
... delta1 = np.diff(price_data.adj_close) / price_data.adj_close[:-1]
... 
... # Marker size in units of points^2
... volume = (15 * price_data.volume[:-2] / price_data.volume[0])**2
... close = 0.003 * price_data.close[:-2] / 0.003 * price_data.open[:-2]
... 
... fig, ax = plt.subplots()
... ax.scatter(delta1[:-1], delta1[1:], c=close, s=volume, alpha=0.5)
... 
... ax.set_xlabel(r'$\Delta_i$', fontsize=15)
... ax.set_ylabel(r'$\Delta_{i+1}$', fontsize=15)
... ax.set_title('Volume and percent change')
... 
... ax.grid(True)
... fig.tight_layout()
... 
... plt.show()
...