Not managing to get an algorithm to work

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posted Nov 10, 2019

I am new with Quantopian/Python and have looked at an algorithm to try to implement. I am for some reason getting Error 50: SyntaxError: expected an indented block when trying to 'build the algorithm' and an error when trying to run the backtes. If someone has the knowledge to help, it would be appreciated a million!

The code:

from quantopian.algorithm import attach_pipeline, pipeline_output
from quantopian.pipeline import Pipeline
import quantopian.pipeline.factors as Factors
import quantopian.pipeline.filters as Filters
from quantopian.pipeline.filters import QTradableStocksUS
from quantopian.pipeline.data.builtin import USEquityPricing
from quantopian.pipeline.data import morningstar
import numpy as pn
import pandas as pd
def initialize(context):
attach_pipeline(my_pipeline(context), name='my_pipe')
schedule_function(rebalance,
date_rule=date_rules.month_start(),
time_rule=time_rules.market_open())
def my_pipeline(context):
pass
market_cap = morningstar.valuation.market_cap.latest
roic = morningstar.operation_ratios.roic.latest
revenue_growth = morningstar.operation_ratios.revenue_growth.latest
shares_outstanding = morningstar.valuation.shares_outstanding.latest
ev_to_ebitda = morningstar.valuation_ratios.ev_to_ebitda.latest

market_cap_ok = market_cap > 100000000  
roic_ok = roic > 0.1  
revenue_growth_ok = revenue_growth > 0  
shares_outstanding_ok = shares_outstanding.notnull()  

my_mask = roic_ok & revenue_growth_ok & shares_outstanding_ok

return Pipeline(  
columns={},  
screen = ev_to_ebitda.bottom(20, mask = my_mask)  
)

def before_trading_start(context, data):
context.output = pipeline_output('my_pipe')
record (cash = context.portfolio.cash, asset = context.portfolio_value)

def rebalance(context, data):
for stock in context.portfolio.positions:
if stock not in context.output.index:
order_target(stock, 0)

weight = create_weights(context, context.output.index, data)  

for stock in context.output.index:  
    if data.can_trade(stock, weight);

def create_weights(context, stocks, data):

cantradecount = 0;  
for stock in stocks:  
    if data.can_trade(stock):  
        cantradecount += 1  

if cantradecount == 0:  
    return 0  
else:  
    weight = 1.0/cantradecount  
    return weight

5 responses

Jonas

Nov 10, 2019

Bumping, anyone that knows what might be wrong? Help please

Dan Whitnable

Nov 10, 2019

The python error 'SyntaxError: expected an indented block' usually occurs after an 'if' or 'for', or some other statement where an indented block of code is expected below it. For example, take the following code

for stock in context.output.index:  
print('oops')

Python gets confused because it is expecting the code after the 'for' statement to be indented. Like this

for stock in context.output.index:  
    print('oops')

So, specifically, the issue with the code above is this statement. The 'if' doesn't have an indented block below it.

for stock in context.output.index:  
    if data.can_trade(stock, weight);

Looks like the code was just unfinished or copied and pasted incorrectly? The data.can_trade method has the wrong parameters and looks more like you intended an order method? In any case, attached is the algo which has these things fixed and I believe is what you intended?

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Jonas

Nov 11, 2019

Hi Dan Whitnable. Big thanks, this helped me immensely! Lastly I would like to ask about the market cap restriction (above $100.000.000). I am getting the error 'Local variable assigned but never used' regarding the market_cap_ok part of the code. What could be the reason for that?

Dan Whitnable

Nov 11, 2019

The reason you are getting the warning Local variable assigned but never used is that the code assigns a value to 'market_cap_ok'. However, this is never used.

    market_cap_ok = market_cap > 100000000

Did you intend to use it in your 'my_mask' filter? Perhaps like this

    my_mask = market_cap_ok  & roic_ok & revenue_growth_ok & shares_outstanding_ok

In any case it's simply a for information only warning. It's not an error. The code will run fine 'as is'.

Disclaimer

Jonas

Nov 12, 2019

Thank you for the answers! Im still very confused as to why the result in the backtesting are largely negative. My aim is to make it pick firms with a market cap larger than 100.000.000, a ROIC larger than 10%, revenue growth larger than 0 and then pick the 20 firms with the lowest EV/EBITDA. Might something else in the code be wrong?

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