.. _pylab_examples-scatter_demo2: pylab_examples example code: scatter_demo2.py ============================================= .. plot:: /home/tcaswell/source/p/matplotlib/doc/mpl_examples/pylab_examples/scatter_demo2.py :: """ 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 python datetime.date as an object array in # the date column datafile = cbook.get_sample_data('goog.npy') try: # Python3 cannot load python2 .npy files with datetime(object) arrays # unless the encoding is set to bytes. Hovever this option was # not added until numpy 1.10 so this example will only work with # python 2 or with numpy 1.10 and later price_data = np.load(datafile, encoding='bytes').view(np.recarray) except TypeError: price_data = np.load(datafile).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=20) ax.set_ylabel(r'$\Delta_{i+1}$', fontsize=20) ax.set_title('Volume and percent change') ax.grid(True) fig.tight_layout() plt.show() Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)