matplotlib Code

import os, sys, datetime, csv, time
import matplotlib.numerix as nx
from matplotlib.dates import date2num, datestr2num
from matplotlib.mlab import load, dist
from pylab import figure, show, draw
import dateutil.parser

datadir = os.path.join('..', 'data')
tickerfile = os.path.join(datadir, 'nasdaq100.dat')
tickers = [line.strip() for line in file(tickerfile)]

def autocorr(x, lag=1):
    """Returns the autocorrelation x."""
    x = nx.asarray(x)
    mu = nx.mlab.mean(x)
    sigma = nx.mlab.std(x)
    return nx.dot(x[:-lag]-mu, x[lag:]-mu)/(sigma**2.)/(len(x) - lag)

# snippet 2 date converters

class DailyData:

    def __init__(self, ticker):
        # load assumes floats unless you provide a converter
        # dictionary keyed by column number
        self.ticker = ticker
        tickerfile = os.path.join(datadir, '%s.csv'%ticker)
        
        # datestr2num is slow but it's easy
        (self.date, self.open, self.high, self.low,
         self.close, self.volume, self.adjclose) = load(
            tickerfile, delimiter=',',
            #converters={0:to_datenum2},            
            converters={0:datestr2num},
            skiprows=1, unpack=True)            

if 1:  # pay the load only once in interactive mode
    tickerd = dict()
    for ticker in tickers:
        tickerd[ticker] = DailyData(ticker)


class ScatterPoint:
    """
    Create an interface to scatter plot point where individual points
    can be selected and introspected.  We can represent four
    dimensions in a scatter: x, y, size and color.  The object will
    provide a method for each of those, and a method called"plotdata"
    which will provide a detail plot of the underlying data

    Derived classes mush define the following attributes 
      x: x axis data value as a scale'
      y: y axis data value as a scalar'
      size: the size the scatter marker in points^2'
      color: the color of the marker; can be a colormappable scalar'
      """

    def plotraw(self):
        'plot the raw data'
        pass



class DailyPoint(ScatterPoint):

    def __init__(self, dailydata):
        self.dailydata = dailydata

        close = dailydata.close

        mu, sigma = nx.mlab.mean, nx.mlab.std

        # compute some statistics of daily and total returns
        self.dailyreturn = g = (close[1:]-close[:-1])/close[:-1]
        self.totalreturn = (close[-1] - close[0])/close[0]
        self.mudaily = mu(g)
        self.sigmadaily = sigma(g)
        self.totalvolume = sigma(dailydata.volume)
        self.lag1corr = autocorr(g, lag=1)

        # Assign the attributes needed for the scatter point interface
        self.x = self.lag1corr
        self.y = self.sigmadaily
        self.size = nx.log(self.totalvolume)
        self.color = self.totalreturn

    def plotraw(self):
        fig = figure()
        dd = self.dailydata
        fig.clf()
        ax1 = fig.add_subplot(211)
        ax1.plot_date(dd.date, dd.close, '-')
        
        ax2 = fig.add_subplot(212) # sharex
        ax2.bar(dd.date, dd.volume)
        ax2.xaxis_date()

        ## snippet 3 customizations

        draw()

## snippet 4: button press handling
        
if 1:
    points = [DailyPoint(dailydata) for dailydata in tickerd.values()]
    data = [(p.x, p.y, p.size, p.color) for p in points]
    x, y, size, color = zip(*data)

    fig = figure(1); fig.clf()
    ax = fig.add_subplot(111)
    ax.scatter(x, y, size, color, alpha=0.75)
    #fig.canvas.mpl_connect('button_press_event', onpress)

show()