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from __future__ import division
from pandas import Series, DataFrame
import pandas as pd
from numpy.random import randn
import numpy as np
pd.options.display.max_rows = 12
np.set_printoptions(precision=4, suppress=True)
import matplotlib.pyplot as plt
plt.rc('figure', figsize=(12, 6))
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%matplotlib inline
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%pwd
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%cd ../book_scripts
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close_px = pd.read_csv('ch11/stock_px.csv', parse_dates=True, index_col=0)
volume = pd.read_csv('ch11/volume.csv', parse_dates=True, index_col=0)
prices = close_px.ix['2011-09-05':'2011-09-14', ['AAPL', 'JNJ', 'SPX', 'XOM']]
volume = volume.ix['2011-09-05':'2011-09-12', ['AAPL', 'JNJ', 'XOM']]
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prices
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volume
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prices * volume
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vwap = (prices * volume).sum() / volume.sum()
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vwap
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vwap.dropna()
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prices.align(volume, join='inner')
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s1 = Series(range(3), index=['a', 'b', 'c'])
s2 = Series(range(4), index=['d', 'b', 'c', 'e'])
s3 = Series(range(3), index=['f', 'a', 'c'])
DataFrame({'one': s1, 'two': s2, 'three': s3})
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DataFrame({'one': s1, 'two': s2, 'three': s3}, index=list('face'))
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ts1 = Series(np.random.randn(3),
index=pd.date_range('2012-6-13', periods=3, freq='W-WED'))
ts1
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ts1.resample('B')
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ts1.resample('B', fill_method='ffill')
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dates = pd.DatetimeIndex(['2012-6-12', '2012-6-17', '2012-6-18',
'2012-6-21', '2012-6-22', '2012-6-29'])
ts2 = Series(np.random.randn(6), index=dates)
ts2
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ts1.reindex(ts2.index, method='ffill')
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ts2 + ts1.reindex(ts2.index, method='ffill')
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gdp = Series([1.78, 1.94, 2.08, 2.01, 2.15, 2.31, 2.46],
index=pd.period_range('1984Q2', periods=7, freq='Q-SEP'))
infl = Series([0.025, 0.045, 0.037, 0.04],
index=pd.period_range('1982', periods=4, freq='A-DEC'))
gdp
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infl
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infl_q = infl.asfreq('Q-SEP', how='end')
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infl_q
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infl_q.reindex(gdp.index, method='ffill')
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# Make an intraday date range and time series
rng = pd.date_range('2012-06-01 09:30', '2012-06-01 15:59', freq='T')
# Make a 5-day series of 9:30-15:59 values
rng = rng.append([rng + pd.offsets.BDay(i) for i in range(1, 4)])
ts = Series(np.arange(len(rng), dtype=float), index=rng)
ts
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from datetime import time
ts[time(10, 0)]
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ts.at_time(time(10, 0))
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ts.between_time(time(10, 0), time(10, 1))
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np.random.seed(12346)
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# Set most of the time series randomly to NA
indexer = np.sort(np.random.permutation(len(ts))[700:])
irr_ts = ts.copy()
irr_ts[indexer] = np.nan
irr_ts['2012-06-01 09:50':'2012-06-01 10:00']
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selection = pd.date_range('2012-06-01 10:00', periods=4, freq='B')
irr_ts.asof(selection)
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data1 = DataFrame(np.ones((6, 3), dtype=float),
columns=['a', 'b', 'c'],
index=pd.date_range('6/12/2012', periods=6))
data2 = DataFrame(np.ones((6, 3), dtype=float) * 2,
columns=['a', 'b', 'c'],
index=pd.date_range('6/13/2012', periods=6))
spliced = pd.concat([data1.ix[:'2012-06-14'], data2.ix['2012-06-15':]])
spliced
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data2 = DataFrame(np.ones((6, 4), dtype=float) * 2,
columns=['a', 'b', 'c', 'd'],
index=pd.date_range('6/13/2012', periods=6))
spliced = pd.concat([data1.ix[:'2012-06-14'], data2.ix['2012-06-15':]])
spliced
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spliced_filled = spliced.combine_first(data2)
spliced_filled
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spliced.update(data2, overwrite=False)
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spliced
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cp_spliced = spliced.copy()
cp_spliced[['a', 'c']] = data1[['a', 'c']]
cp_spliced
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import pandas.io.data as web
price = web.get_data_yahoo('AAPL', '2011-01-01')['Adj Close']
price[-5:]
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price['2011-10-03'] / price['2011-3-01'] - 1
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returns = price.pct_change()
ret_index = (1 + returns).cumprod()
ret_index[0] = 1 # Set first value to 1
ret_index
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m_returns = ret_index.resample('BM', how='last').pct_change()
m_returns['2012']
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m_rets = (1 + returns).resample('M', how='prod', kind='period') - 1
m_rets['2012']
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pd.options.display.max_rows = 100
pd.options.display.max_columns = 10
np.random.seed(12345)
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import random; random.seed(0)
import string
N = 1000
def rands(n):
choices = string.ascii_uppercase
return ''.join([random.choice(choices) for _ in xrange(n)])
tickers = np.array([rands(5) for _ in xrange(N)])
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M = 500
df = DataFrame({'Momentum' : np.random.randn(M) / 200 + 0.03,
'Value' : np.random.randn(M) / 200 + 0.08,
'ShortInterest' : np.random.randn(M) / 200 - 0.02},
index=tickers[:M])
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ind_names = np.array(['FINANCIAL', 'TECH'])
sampler = np.random.randint(0, len(ind_names), N)
industries = Series(ind_names[sampler], index=tickers,
name='industry')
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by_industry = df.groupby(industries)
by_industry.mean()
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by_industry.describe()
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# Within-Industry Standardize
def zscore(group):
return (group - group.mean()) / group.std()
df_stand = by_industry.apply(zscore)
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df_stand.groupby(industries).agg(['mean', 'std'])
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# Within-industry rank descending
ind_rank = by_industry.rank(ascending=False)
ind_rank.groupby(industries).agg(['min', 'max'])
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# Industry rank and standardize
by_industry.apply(lambda x: zscore(x.rank()))
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from numpy.random import rand
fac1, fac2, fac3 = np.random.rand(3, 1000)
ticker_subset = tickers.take(np.random.permutation(N)[:1000])
# Weighted sum of factors plus noise
port = Series(0.7 * fac1 - 1.2 * fac2 + 0.3 * fac3 + rand(1000),
index=ticker_subset)
factors = DataFrame({'f1': fac1, 'f2': fac2, 'f3': fac3},
index=ticker_subset)
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factors.corrwith(port)
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pd.ols(y=port, x=factors).beta
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def beta_exposure(chunk, factors=None):
return pd.ols(y=chunk, x=factors).beta
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by_ind = port.groupby(industries)
exposures = by_ind.apply(beta_exposure, factors=factors)
exposures.unstack()
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import pandas.io.data as web
data = web.get_data_yahoo('SPY', '2006-01-01')
data.info()
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px = data['Adj Close']
returns = px.pct_change()
def to_index(rets):
index = (1 + rets).cumprod()
first_loc = max(index.index.get_loc(index.idxmax()) - 1, 0)
index.values[first_loc] = 1
return index
def trend_signal(rets, lookback, lag):
signal = pd.rolling_sum(rets, lookback, min_periods=lookback - 5)
return signal.shift(lag)
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signal = trend_signal(returns, 100, 3)
trade_friday = signal.resample('W-FRI').resample('B', fill_method='ffill')
trade_rets = trade_friday.shift(1) * returns
trade_rets = trade_rets[:len(returns)]
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to_index(trade_rets).plot()
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vol = pd.rolling_std(returns, 250, min_periods=200) * np.sqrt(250)
def sharpe(rets, ann=250):
return rets.mean() / rets.std() * np.sqrt(ann)
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cats = pd.qcut(vol, 4)
print('cats: %d, trade_rets: %d, vol: %d' % (len(cats), len(trade_rets), len(vol)))
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trade_rets.groupby(cats).agg(sharpe)
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names = ['AAPL', 'GOOG', 'MSFT', 'DELL', 'GS', 'MS', 'BAC', 'C']
def get_px(stock, start, end):
return web.get_data_yahoo(stock, start, end)['Adj Close']
px = DataFrame({n: get_px(n, None, None) for n in names})
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px = pd.read_pickle('notebooks/stock_prices')
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plt.close('all')
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px = px.asfreq('B').fillna(method='pad')
rets = px.pct_change()
((1 + rets).cumprod() - 1).plot()
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def calc_mom(price, lookback, lag):
mom_ret = price.shift(lag).pct_change(lookback)
ranks = mom_ret.rank(axis=1, ascending=False)
demeaned = ranks.subtract(ranks.mean(axis=1), axis=0)
return demeaned.divide(demeaned.std(axis=1), axis=0)
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compound = lambda x : (1 + x).prod() - 1
daily_sr = lambda x: x.mean() / x.std()
def strat_sr(prices, lb, hold):
# Compute portfolio weights
freq = '%dB' % hold
port = calc_mom(prices, lb, lag=1)
daily_rets = prices.pct_change()
# Compute portfolio returns
port = port.shift(1).resample(freq, how='first')
returns = daily_rets.resample(freq, how=compound)
port_rets = (port * returns).sum(axis=1)
return daily_sr(port_rets) * np.sqrt(252 / hold)
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strat_sr(px, 70, 30)
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from collections import defaultdict
lookbacks = range(20, 90, 5)
holdings = range(20, 90, 5)
dd = defaultdict(dict)
for lb in lookbacks:
for hold in holdings:
dd[lb][hold] = strat_sr(px, lb, hold)
ddf = DataFrame(dd)
ddf.index.name = 'Holding Period'
ddf.columns.name = 'Lookback Period'
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import matplotlib.pyplot as plt
def heatmap(df, cmap=plt.cm.gray_r):
fig = plt.figure()
ax = fig.add_subplot(111)
axim = ax.imshow(df.values, cmap=cmap, interpolation='nearest')
ax.set_xlabel(df.columns.name)
ax.set_xticks(np.arange(len(df.columns)))
ax.set_xticklabels(list(df.columns))
ax.set_ylabel(df.index.name)
ax.set_yticks(np.arange(len(df.index)))
ax.set_yticklabels(list(df.index))
plt.colorbar(axim)
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heatmap(ddf)
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pd.options.display.max_rows = 10
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import pandas.io.data as web
# Approximate price of S&P 500 index
px = web.get_data_yahoo('SPY')['Adj Close'] * 10
px
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from datetime import datetime
expiry = {'ESU2': datetime(2012, 9, 21),
'ESZ2': datetime(2012, 12, 21)}
expiry = Series(expiry).order()
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expiry
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np.random.seed(12347)
N = 200
walk = (np.random.randint(0, 200, size=N) - 100) * 0.25
perturb = (np.random.randint(0, 20, size=N) - 10) * 0.25
walk = walk.cumsum()
rng = pd.date_range(px.index[0], periods=len(px) + N, freq='B')
near = np.concatenate([px.values, px.values[-1] + walk])
far = np.concatenate([px.values, px.values[-1] + walk + perturb])
prices = DataFrame({'ESU2': near, 'ESZ2': far}, index=rng)
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prices.tail()
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def get_roll_weights(start, expiry, items, roll_periods=5):
# start : first date to compute weighting DataFrame
# expiry : Series of ticker -> expiration dates
# items : sequence of contract names
dates = pd.date_range(start, expiry[-1], freq='B')
weights = DataFrame(np.zeros((len(dates), len(items))),
index=dates, columns=items)
prev_date = weights.index[0]
for i, (item, ex_date) in enumerate(expiry.iteritems()):
if i < len(expiry) - 1:
weights.ix[prev_date:ex_date - pd.offsets.BDay(), item] = 1
roll_rng = pd.date_range(end=ex_date - pd.offsets.BDay(),
periods=roll_periods + 1, freq='B')
decay_weights = np.linspace(0, 1, roll_periods + 1)
weights.ix[roll_rng, item] = 1 - decay_weights
weights.ix[roll_rng, expiry.index[i + 1]] = decay_weights
else:
weights.ix[prev_date:, item] = 1
prev_date = ex_date
return weights
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weights = get_roll_weights('6/1/2012', expiry, prices.columns)
weights.ix['2012-09-12':'2012-09-21']
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rolled_returns = (prices.pct_change() * weights).sum(1)
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aapl = web.get_data_yahoo('AAPL', '2000-01-01')['Adj Close']
msft = web.get_data_yahoo('MSFT', '2000-01-01')['Adj Close']
aapl_rets = aapl.pct_change()
msft_rets = msft.pct_change()
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plt.figure()
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pd.rolling_corr(aapl_rets, msft_rets, 250).plot()
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plt.figure()
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model = pd.ols(y=aapl_rets, x={'MSFT': msft_rets}, window=250)
model.beta
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model.beta['MSFT'].plot()