How can I replace this portion of code with data coming from Quandl ? my understanding is that context.SPY and context.AAPL refer to symbols in Quantopian database and declared with :

context.SPY = symbol('SPY')  
context.AAPL = symbol('AAPL')  

In this code :

def handle_data(context, data):

    prices = history(30, '1d', 'price')  
    ratio = prices[context.SPY] / prices[context.AAPL]  
    ma = talib.MA(ratio, 14)[-1:]  
    record(MA_Of_Ratio=float(ma))  

How can I use VIX and VXV instead of AAPL and SPY ?

def initialize(context):

    fetch_csv('http://www.quandl.com/api/v1/datasets/CBOEFE/INDEX_VXV.csv?trim_start=2012-01-01',  
        date_column='Date',  
        symbol='VXV',  
        post_func=rename_col,  
        date_format='%d-%m-%Y')

    fetch_csv('http://www.quandl.com/api/v1/datasets/CBOEFE/INDEX_VIX.csv?trim_start=2012-01-01',  
        date_column='Date',  
        symbol='VIX',  
        post_func=rename_col,  
        date_format='%d-%m-%Y')  
    context.VIX = 'VIX'  
    context.VXV = 'VXV'  

context.VIX = 'VIX' returns error :(

Any idea why I have this error with the code bellow ?
I can plot VIX et VXV separately with .price attribute, it is not clear for me with there is such error.
Thank's!

AttributeError: 'SIDData' object has no attribute 'price'
USER ALGORITHM:39, in handle_data
ratio = (data['VXV'].price / data['VIX'].price)

import pandas

def rename_col(df):  
    df = df.rename(columns={'CLOSE': 'price'})  
    df = df.rename(columns={'VIX Close': 'price'})  
    df = df.rename(columns={'Equity Put Volume': 'price'})  
    df = df.fillna(method='ffill')  
    df = df[['price', 'sid']]  
    # Correct look-ahead bias in mapping data to times  
    df = df.tshift(1, freq='b')  
    log.info(' \n %s ' % df.head())  
    return df  
def initialize(context):  
    # import the external data  
    fetch_csv('http://www.quandl.com/api/v1/datasets/CBOE/EQUITY_PC.csv?trim_start=2012-01-01',  
        date_column='Date',  
        symbol='PutVolume',  
        post_func=rename_col,  
        date_format='%d-%m-%Y')

    fetch_csv('http://www.quandl.com/api/v1/datasets/CBOEFE/INDEX_VXV.csv?trim_start=2012-01-01',  
        date_column='Date',  
        symbol='VXV',  
        post_func=rename_col,  
        date_format='%d-%m-%Y')

    fetch_csv('http://www.quandl.com/api/v1/datasets/CBOEFE/INDEX_VIX.csv?trim_start=2012-01-01',  
        date_column='Date',  
        symbol='VIX',  
        post_func=rename_col,  
        date_format='%d-%m-%Y')  
    # SPX  
    context.SPY = symbol('SPY')

def handle_data(context, data):

    ratio = (data['VXV'].price / data['VIX'].price)  

get it

I'm having a similar error getting AttributeError: 'SIDData' object has no attribute 'price' - did you ever get it figured out?

This usually happens if you're trying to get the price of a stock in a minute that it didn't trade.

You can add this guard to check there is price data for the security: (or in this case, the instrument)

if 'VXV' and 'VIX' in data:  
     ratio = (data['VXV'].price / data['VIX'].price)  

If your code is structured in a different way (hard-coded list of stocks, using a fundamentals or set_universe screener) then you can do:

for stock in data:  #loop through your list of stocks  
    if stock in data:  # check there is price data in this bar  
        price = data[stock].price   # access the price  

You can also see more info here: https://www.quantopian.com/help#api-common-errors

Vix is an index not an ETF

Thanks - what an odd piece of code to need though, as for stock in data: should iterate through all the stocks in data, making the beck unnecessary. I suppose it has to do with the way the underlying zipline objects are overloaded dict-like obejcts: perhaps overloading in for if stock in data compares a bunch of attributes, not just existence. Thanks!

@florent: what are reading/signalling with the PC ratio's? Any insights?

I cant manage to fetch the data. for some reason all entriesare empty, even though the CSV previous seems to show data. anyone can help ? this fetcher is hard to debug

I have some magic for you: uncomment

#context.SPY = symbol('SPY')  

.... and it the data will be in DATA... not in history though... you have to merge the data into history if you really want it

yes it works ... very strange wonder why

Magic!

Each algo needs at least one declared symbol. One of the quirks of fetcher.