Python Tutorial – Getting Started

Contact: andrewshamlet@gmail.com // @andrewshamlet

Getting Started

Congratulations, and welcome to Stock Technical Analysis in Python!

You have taken your first step towards making smarter, more disciplined trading decisions.

Before diving in, let’s make sure you have everything you may need.

Anaconda 4.4.0

We recommend downloading Anaconda 4.4.0, with Python 2.7.

– http://www.continuum.io/downloads

Pandas, Numpy, and MatPlotLib

Anaconda comes pre-loaded with the three modules you will use throughout the course.

– http://www.pandas.pydata.org/

– http://www.numpy.org/

– http://www.matplotlib.org/

Quantopian

You will backtest your strategy using the Quantopian platform.-

– http://www.quantopian.com/

StockCharts, Investopedia, and Google Finance

StockCharts, Investopedia, and Google Finance are great resources for financial knowledge.

– http://www.stockcharts.com

– http://www.investopedia.com/

– http://www.google.com/finance

Stack Overflow

Stack Overflow is a great resource for coding questions.-

– http://www.stackoverflow.com/

You are now ready to dive in!

Capitalism 2.0 Will Include a Healthy Dose of Socialism | Eric Weinstein

 

 

‘We never saw that capitalism may be defeated by its own child, Technology’

‘Markets only really work when the value of something and the price of that good or service coincide’

‘What causes value and price to get out of alignment?’

‘Technology figures out the small size of market failures and make it rather large’

‘Musicians went from producing a private good, where price and value coincided, to in fact producing a public good’

‘The idea of taxing people to pay for a standing army and their steady diet of jazz and rock and roll probably didn’t make a lot of sense’

‘The portion of the pie that is private goods is likely to shrink’

‘Traditionally, technology has moved us from low value occupations to higher value occupations’

‘Almost all code can be broken into two kinds: code that runs once and never repeats, and code that loops over and over and over’

‘Unfortunately, what most jobs are, are some version of a loop’

‘Our technical training for occupations moves the entire population into the crosshairs of software’

‘All repetitive behaviors are in the crosshairs of software’

‘We still have the Rube Goldberg section of codes, where something happens once, never to be repeated’

‘A poem will be composed that will never need to be recomposed’

‘Most people do not see themselves as capable of doing these one off acts of inspiration, that will probably always be fairly highly rewarded’

‘They see themselves as needing a repetitive behavior on which they can build their families, hopes, and dreams’

‘That era may have changed’

‘So many souls will require respect, hope, freedom, and choice who may not be able to defend themselves in the market as our software and machines continue to get better and better’

‘This is reason why something like universal basic income comes out of a place as fiercely capitalistic as Silicon Valley’

‘These are the folks who are closest to seeing the destruction that their work may visit upon the population’

‘Technology is forcing those who are more familiar with it to become the most compassionate’

‘I’m rather confused about whether to be optimistic or pessimistic’

‘Our government is populated by people who come from softer disciplines, whether that is law or poli sci’

‘Very few people in government come from a hardcore technical background’

‘There are very few senators who can solve a partial differential equation or program a computer’

‘This is a terrible inversion of what should be happening’

‘The technical professions were turned into support roles for this leadership class’

‘During the 1950s there was a tremendous vogue for thinking of a technical intellectual elite who could in fact lead us to a more hopeful, technological, scientific tomorrow’

‘Somewhere along the line, that got lost’

‘We have the technical talent to build an optimistic future’

‘For whatever reason, we are so terrified now of those technical folks, that we keep attempting to subordinate them’

‘If you look at a society like China’s, China is certainly not falling for this trap–they are proceeding along a very different path’

‘Whether or not we understand where we are and make the correct decisions for an optimistic future, depends as to whether we have the right leadership class’

‘Do we realize that the technical people should have been making the decisions all along’

Python Tutorial: Price Channels

Download the accompanying IPython Notebook for this Tutorial from Github. 

 

Python streamlines tasks requiring multiple steps in a single block of code. For this reason, it is a great tool for querying and performing analysis on stock ticker data.

Last post, we outlined steps for calculating Bollinger Bands.

In this post, we introduce a new technical indicator,  Price Channels.

Price Channels

Price Channels are lines set above and below the price of a security. The upper channel is set at the x-period high and the lower channel is set at the x-period low. For a 20-day Price Channel, the upper channel would equal the 20-day high and the lower channel would equal the 20-day low.

Price Channels can be used to identify upward thrusts that signal the start of an uptrend or downward plunges that signal the start of a downtrend. Price Channels can also be used to identify overbought or oversold levels within a bigger downtrend or uptrend.

Price Channels are calculated as follows:

Upper Channel: 20-day high
Lower Channel: 20-day low

Let’s use Python to compute Price Channels.

1. Import modules.

import pandas as pd
import pandas.io.data as web
import matplotlib.pyplot as plt
%matplotlib inline

2. Define function for querying the daily high.

def get_high(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['High']

3. Define function for querying the daily low.

def get_low(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Low']

4. Define function for querying daily close.

def get_close(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Adj Close']

5. Query daily high, daily low, and daily close for ‘FB’ during 2016.

x = pd.DataFrame(get_high('FB', '1/1/2016', '12/31/2016'))
x['Low'] = pd.DataFrame(get_low('FB', '1/1/2016', '12/31/2016'))
x['Close'] = pd.DataFrame(get_close('FB', '1/1/2016', '12/31/2016'))

6. Compute 4 week high and 4 week low using rolling max/min. Add 50 day simple moving average for good measure.

x['4WH'] = pd.rolling_max(x['High'], 20)
x['4WL'] = pd.rolling_min(x['Low'], 20)
x['50 sma'] = pd.rolling_mean(x['Close'], 50)

7. Plot 4WH, 4WL, 50 sma, and daily close.

x.plot(y=['4WH', '4WL', '50 sma', 'Close'])

There you have it! We created our Price Channels. Here’s the full code:

import pandas as pd 
import pandas.io.data as web 
import matplotlib.pyplot as plt
%matplotlib inline

def get_high(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['High']
def get_low(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Low']
def get_close(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Adj Close']

x = pd.DataFrame(get_high('FB', '1/1/2016', '12/31/2016'))
x['Low'] = pd.DataFrame(get_low('FB', '1/1/2016', '12/31/2016'))
x['Close'] = pd.DataFrame(get_close('FB', '1/1/2016', '12/31/2016'))

x['4WH'] = pd.rolling_max(x['High'], 20)
x['4WL'] = pd.rolling_min(x['Low'], 20)
x['50 sma'] = pd.rolling_mean(x['Close'], 50)

x.plot(y=['4WH', '4WL', '50 sma', 'Close'])

In celebration of completing this tutorial, let’s watch Ed Seykota sing ‘The Whipsaw Song’.

Python Tutorial: Bollinger Bands

Download the accompanying IPython Notebook for this Tutorial from Github. 

 

Python streamlines tasks requiring multiple steps in a single block of code. For this reason, it is a great tool for querying and performing analysis on data.

Last post, we outlined steps for calculating MACD Signal Line & Centerline Crossovers.

In this post, we introduce a new technical indicator,  Bollinger Bands.

Bollinger Bands

Developed by John Bollinger, Bollinger Bands® are volatility bands placed above and below a moving average. Volatility is based on the standard deviation, which changes as volatility increases and decreases. The bands automatically widen when volatility increases and narrow when volatility decreases. This dynamic nature of Bollinger Bands also means they can be used on different securities with the standard settings. For signals, Bollinger Bands can be used to identify Tops and Bottoms or to determine the strength of the trend.

Bollinger Bands reflect direction with the 20-period SMA and volatility with the upper/lower bands. As such, they can be used to determine if prices are relatively high or low. According to Bollinger, the bands should contain 88-89% of price action, which makes a move outside the bands significant. Technically, prices are relatively high when above the upper band and relatively low when below the lower band. However, relatively high should not be regarded as bearish or as a sell signal. Likewise, relatively low should not be considered bullish or as a buy signal. Prices are high or low for a reason. As with other indicators, Bollinger Bands are not meant to be used as a stand alone tool. Chartists should combine Bollinger Bands with basic trend analysis and other indicators for confirmation.

Bollinger Bands are calculated as follows:

Middle Band = 20 day moving average
Upper Band = 20 day moving average + (20 Day standard deviation of price x 2) 
Lower Band = 20 day moving average - (20 Day standard deviation of price x 2)

Bollinger Bands consist of a middle band with two outer bands. The middle band is a simple moving average that is usually set at 20 periods. A simple moving average is used because the standard deviation formula also uses a simple moving average. The look-back period for the standard deviation is the same as for the simple moving average. The outer bands are usually set 2 standard deviations above and below the middle band.

Let’s use Python to compute Bollinger Bands.

1. Start with the 30 Day Moving Average Tutorial code.

import pandas as pd
import pandas.io.data as web
%matplotlib inline
import matplotlib.pyplot as plt

stocks = ['FB']
def get_stock(stock, start, end):
     return web.get_data_yahoo(stock, start, end)['Adj Close']
px = pd.DataFrame({n: get_px(n, '1/1/2016', '12/31/2016') for n in names})
px

2. Compute the 20 Day Moving Average.

px['20 ma'] = pd.stats.moments.rolling_mean(px['FB'],20)

3. Compute 20 Day Standard Deviation. 

px['20 sd'] = pd.stats.moments.rolling_std(px['FB'],20)

4. Create Upper Band.

px['Upper Band'] = px['20 ma'] + (px['20 sd']*2)

5. Create Lower Band.

px['Lower Band'] = px['20 ma'] - (px['20 sd']*2)

6. Plot Bollinger Bands.

px.plot(y=['FB','20 ma', 'Upper Band', 'Lower Band'], title='Bollinger Bands')

There you have it! We created our Bollinger Bands. Here’s the full code:

import pandas as pd
import pandas.io.data as web
%matplotlib inline
import matplotlib.pyplot as plt

stocks = ['FB']
def get_stock(stock, start, end):
     return web.get_data_yahoo(stock, start, end)['Adj Close']
px = pd.DataFrame({n: get_px(n, '1/1/2016', '12/31/2016') for n in names})
px['20 ma'] = pd.stats.moments.rolling_mean(px['FB'],20)
px['20 sd'] = pd.stats.moments.rolling_std(px['FB'],20)
px['Upper Band'] = px['20 ma'] + (px['20 sd']*2)
px['Lower Band'] = px['20 ma'] - (px['20 sd']*2)
px.plot(y=['FB','20 ma', 'Upper Band', 'Lower Band'], title='Bollinger Bands')

Python Tutorial: MACD Signal Line & Centerline Crossovers

Python streamlines tasks requiring multiple steps in a single block of code. For this reason, it is a great tool for querying and performing analysis on data.

Last post, we outlined steps for calculating a stock’s MACD indicator.

In this post, we take MACD a step further by introducing Signal Line and Centerline Crossovers.

Signal Line Crossovers

Signal Line is defined as:

Signal Line: 9-day EMA of MACD Line

Signal line crossovers are the most common MACD signals. The signal line is a 9-day EMA of the MACD Line. As a moving average of the indicator, it trails the MACD and makes it easier to spot MACD turns. A bullish crossover occurs when the MACD turns up and crosses above the signal line. A bearish crossover occurs when the MACD turns down and crosses below the signal line. Crossovers can last a few days or a few weeks, it all depends on the strength of the move.

Let’s use Python to compute the Signal Line.

1.  Start with the MACD Tutorial code.

import pandas.io.data as web 
import pandas as pd 
%matplotlib inline 
import matplotlib.pyplot as plt 

names = ['FB'] 

def get_px(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Adj Close'] 
px = pd.DataFrame({n: get_px(n, '1/1/2016', '1/17/2017') for n in names}) 
px['26 ema'] = pd.ewma(px["FB"], span=26) 
px['12 ema'] = pd.ewma(px["FB"], span=12) 
px['MACD'] = (px['12 ema'] - px['26 ema'])

2. Compute the 9 Day Exponential Moving Average of MACD.

px['Signal Line'] = pd.ewma(px['MACD'], span=9)

3. Create Signal Line Crossover Indicator. When MACD > Signal Line, 1. When MACD < Signal Line, 0.

px['Signal Line Crossover'] = np.where(px['MACD'] > px['Signal Line'], 1, 0)
px['Signal Line Crossover'] = np.where(px['MACD'] < px['Signal Line'], -1, px['Signal Line Crossover'])

Centerline Crossovers

Centerline crossovers are the next most common MACD signals. A bullish centerline crossover occurs when the MACD Line moves above the zero line to turn positive. This happens when the 12-day EMA of the underlying security moves above the 26-day EMA. A bearish centerline crossover occurs when the MACD moves below the zero line to turn negative. This happens when the 12-day EMA moves below the 26-day EMA.

Centerline crossovers can last a few days or a few months. It all depends on the strength of the trend. The MACD will remain positive as long as there is a sustained uptrend. The MACD will remain negative when there is a sustained downtrend.

4. Create Centerline Crossover Indicator. When MACD > 0, 1. When MACD < 0, 0.

px['Centerline Crossover'] = np.where(px['MACD'] > 0, 1, 0)
px['Centerline Crossover'] = np.where(px['MACD'] < 0, -1, px['Centerline Crossover'])

Plotting Crossovers

Last post, we posed the question: ‘When would you enter the position 😕 ?’

Now that we understand Signal Line Crossovers, let’s propose that we enter the position, ‘buy’, on 1, and we exit the position, ‘sell’, on -1.

5. Create Buy/Sell Indicator, based on Signal Line Crossovers. Multiply by 2 to increase size of indicator when plotted, so ‘buy’ on 2 and ‘sell’ on -2.

px['Buy Sell'] = (2*(np.sign(px['Signal Line Crossover'] - px['Signal Line Crossover'].shift(1))))

6. Plot close price, MACD & Signal Line, and Signal Line & Centerline Crossovers.

px.plot(y=['FB'], title='Close')
px.plot(y= ['MACD', 'Signal Line'], title='MACD & Signal Line')
px.plot(y= ['Centerline Crossover', 'Buy Sell'], title='Signal Line & Centerline Crossovers', ylim=(-3,3))

There you have it! We created MACD Signal Line and Centerline Crossovers, and based on the Crossovers, plotted ‘buy’ and ‘sell’ indicators.

Based on the entry and exit points, can you calculate the P&L? Stay tuned to find out.

Here’s the full code:

import pandas.io.data as web 
import pandas as pd 
%matplotlib inline 
import matplotlib.pyplot as plt 

names = ['FB'] 

def get_px(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Adj Close'] 
px = pd.DataFrame({n: get_px(n, '1/1/2016', '1/17/2017') for n in names}) 
px['26 ema'] = pd.ewma(px["FB"], span=26) 
px['12 ema'] = pd.ewma(px["FB"], span=12) 
px['MACD'] = (px['12 ema'] - px['26 ema'])
px['Signal Line'] = pd.ewma(px['MACD'], span=9)
px['Signal Line Crossover'] = np.where(px['MACD'] > px['Signal Line'], 1, 0)
px['Signal Line Crossover'] = np.where(px['MACD'] < px['Signal Line'], -1, px['Signal Line Crossover'])
px['Centerline Crossover'] = np.where(px['MACD'] > 0, 1, 0)
px['Centerline Crossover'] = np.where(px['MACD'] < 0, -1, px['Centerline Crossover'])
px['Buy Sell'] = (2*(np.sign(px['Signal Line Crossover'] - px['Signal Line Crossover'].shift(1))))

px.plot(y=['FB'], title='Close')
px.plot(y= ['MACD', 'Signal Line'], title='MACD & Signal Line')
px.plot(y= ['Centerline Crossover', 'Buy Sell'], title='Signal Line & Centerline Crossovers', ylim=(-3,3))

Python Tutorial: MACD (Moving Average Convergence/Divergence)

Python streamlines tasks requiring multiple steps in a single block of code. For this reason, it is a great tool for querying and performing analysis on data.

In this post, we outline steps for calculating a stock’s MACD indicator. But first, what is MACD (Moving Average Convergence/Divergence)?

Developed by Gerald Appel in the late seventies, MACD is one of the simplest and most effective momentum indicators available. MACD turns two trend-following indicators, moving averages, into a momentum oscillator by subtracting the longer moving average from the shorter moving average. As a result, MACD offers the best of both worlds: trend following and momentum.

To calculate MACD, the formula is:

MACD: (12-day EMA - 26-day EMA)

EMA stands for Exponential Moving Average.

With that background, let’s use Python to compute MACD.

1. Start with the 30 Day Moving Average Tutorial code.

import pandas as pd
import pandas.io.data as web

stocks = ['FB']
def get_stock(stock, start, end):
     return web.get_data_yahoo(stock, start, end)['Adj Close']
px = pd.DataFrame({n: get_px(n, '1/1/2016', '12/31/2016') for n in names})
px

2. Compute the 26 Day Exponential Moving Average. We must call the column by the stock ticker.

px['26 ema'] = pd.ewma(px["FB"], span=26)

3. Then the 12 Day Exponential Moving Average.

px['12 ema'] = pd.ewma(px["FB"], span=12)

4. Subtract the 26 Day EMA from the 12 Day EMA, arriving at the MACD.

px['MACD'] = (px['12 ema'] - px['26 ema'])

5. Plot close price against MACD.

px.plot(y= ['FB'], title='FB')
px.plot(y= ['MACD'], title='MACD')

There you have it! We created our MACD indicator. Here’s the full code:

import pandas.io.data as web
import pandas as pd
%matplotlib inline
import matplotlib.pyplot as plt

names = ['FB']
def get_px(stock, start, end): 
     return web.get_data_yahoo(stock, start, end)['Adj Close']
px = pd.DataFrame({n: get_px(n, '1/1/2016', '1/17/2017') for n in names})
px['26 ema'] = pd.ewma(px["FB"], span=26)
px['12 ema'] = pd.ewma(px["FB"], span=12)
px['MACD'] = (px['12 ema'] - px['26 ema'])
px.plot(y= ['FB'], title='FB')
px.plot(y= ['MACD'], title='MACD')

So when would you enter the position 😕 ?

Python Tutorial: Plot 30 Day Moving Average

Python streamlines tasks requiring multiple steps in a single block of code. For this reason, it is a great tool for querying and performing analysis on data.

Last post we created a DataFrame containing the daily ticker data for a specific stock and calculated its 30 day moving average. In this post, we will take it a step further and plot the DataFrame in order to visualize its contents.

1. Code from last post.

import pandas as pd
import pandas.io.data as web

stocks = ['FB']
def get_stock(stock, start, end):
     return web.get_data_yahoo(stock, start, end)['Adj Close']
px = pd.DataFrame({n: get_px(n, '1/1/2016', '12/31/2016') for n in names})
px['30 mavg'] = pd.rolling_mean(px, 30)
px

2. Import the matplotlib modules.

import matplotlib.pyplot as plt
%matplotlib inline

3. Call the plot function.

plt.plot(px)

There you have it! We used matplotlib to visualize our DataFrame. Looks like the stock tanked towards the end of 2016, perhaps due to the US Presidential Election 😉 

Here is the full code:

import pandas as pd 
import pandas.io.data as web 
import matplotlib.pyplot as plt
%matplotlib inline

stocks = ['FB'] 
def get_stock(stock, start, end):
     return web.get_data_yahoo(stock, start, end)['Adj Close'] 
px = pd.DataFrame({n: get_px(n, '1/1/2016', '12/31/2016') for n in names}) 
px['30 mavg'] = pd.rolling_mean(px, 30) 
plt.plot(px)

Python Tutorial: Query Stock Data, Calculate 30 Day Moving Average

Python streamlines tasks requiring multiple steps in a single block of code. For this reason, it is a great tool for querying and performing analysis on data. In this post we will use Python to pull ticker data for a specific stock and then calculate its 30 day moving average. Here are the steps:

1. Import the pandas modules.

import pandas as pd
import pandas.io.data as web

2. Create a list of the stocks for which you would like to query ticker data. For this example, we will pull ticker data for Facebook, ‘FB’. If you would like to add other stocks, simply add the symbols to the list separated by commas.

stocks = ['FB']

Or

stocks = ['FB','AAPL','GOOG','AMZN']

3. Write function to query data from yahoo finance. The function takes three arguments: the stock, the start date, and the end date. It returns the daily ‘Adj Close’. If you would like to pull a different value, simply switch it for ‘Adj Close’ without the brackets.

def get_stock(stock,start,end):
     return web.get_data_yahoo(stock,start,end)['Adj Close']

Or

def get_stock(stock,start,end):
     return web.get_data_yahoo(stock,start,end)['Volume']

4. Call function for the date range, 1/1/2016 – 12/31/2016. Use the ‘for n in stocks’ logic in case you have more than one stock for which you would like to pull data. Compile query in DataFrame, saved to variable ‘px’.

px = pd.DataFrame({n: get_stock(n, '1/1/2016', '12/31/2016') for n in stocks})

5. Add new column to DataFrame in which you calculate the 30 day moving average. Call DataFrame to view contents.

px['30 mavg'] = pd.rolling_mean(px, 30)
px

There you have it! We created a DataFrame containing the daily ticker data for a specific stock and then calculated its 30 day moving average. Here is the full code:

import pandas as pd
import pandas.io.data as web

stocks = ['FB']
def get_stock(stock, start, end):
     return web.get_data_yahoo(stock, start, end)['Adj Close']
px = pd.DataFrame({n: get_px(n, '1/1/2016', '12/31/2016') for n in names})
px['30 mavg'] = pd.rolling_mean(px, 30)
px