%pylab inline

from IPython import parallel

rc = parallel.Client()
dv = rc[:]
lbv = rc.load_balanced_view()

%%px

import urllib2
from io import BytesIO

from matplotlib import finance

def get_yahoo_data(name=None, start=None, end=None):
    """return historical stock data from yahoo as a recarray."""
    fp = finance.fetch_historical_yahoo(name, start, end)
    return finance.parse_yahoo_historical(fp, asobject=True)

def relative_close(records):
    """return the reative change in closing price over the interval"""
    
    close = records['aclose']
    return (close[-1] - close[0]) / close[0]



%%px
import datetime
end = datetime.datetime.now()
start = end - datetime.timedelta(days=365)

ticker = ['AAPL', 'GOOG', 'MSFT', 'RIMM', 'NOK', 'ORCL', 'AMZN', 'INTC', 'ATVI', 'EA', 'NFLX']

def year_over_year(name):
    """fetch data, and return year-over-year change (relative to first close)
 
    in percent
    """
    stock = get_yahoo_data(name, start, end)
    return relative_close(stock) * 100

amr = lbv.map(year_over_year, ticker)
amr

fig, ax = subplots()
fig.set_figwidth(10)
ax.bar(range(len(amr)), amr)
ax.set_xticks(np.arange(len(amr))+0.4)
ax.set_xticklabels(ticker);
ax.axhline(0, c='k')