Runtime exception: TypeError: 'str' object is not callable

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posted Oct 6, 2014

Hi,

I'm getting this error and don't understand why! Any ideas anyone?

My code is here:

import math  
import talib as ta  
import pandas as pd  
import numpy as np

def initalise_context(sid, context):  
    historical_close = history(bar_count=365, frequency='1d', field='close_price')

    daily_close = historical_close[sid]


def process_order(sid, order, context, close):  
    cash = context.portfolio.cash  
    context.notional = context.notional + context.portfolio.positions[sid].amount * close  
    datetime = pd.Timestamp(get_datetime()).tz_convert('US/Eastern')  
    if ( order.lower()[0][0] == 'b' ):  
        if ( context.notional < context.max_notional ):  
            number_of_shares = int(cash/close)  
            message = '{s}: {o} {n} @ {d}'  
            log.info( message.format( s=sid, o=order, n=number_of_shares, d=datetime ))  
            #order_percent(sid, 0.33, style=MarketOrder(exchange=IBExchange.SMART))  
            order(sid, number_of_shares)  
            context.notional = context.notional + close * number_of_shares  
    else:  
        if ( context.notional > context.min_notional ):  
            number_of_shares = context.portfolio.positions[sid].amount  
            message = '{s}: {o} {n} @ {d}'  
            log.info( message.format( s=sid, o=order, n=number_of_shares, d=datetime ))  
            #order_percent(sid, -0.33, style=MarketOrder(exchange=IBExchange.SMART))  
            order(sid, -number_of_shares)  
            context.notional = context.notional - close * number_of_shares

def initialize(context):  
    context.stocks = [symbol('AAPL'), symbol('MSFT')]  
    context.max_notional = 1000000.1  
    context.min_notional = 20000.0  
    context.notional = 0  
    context.day = None  

def handle_data(context, data):  
    for sid in context.stocks:  
        close = data[sid].close_price  
        if context.portfolio.positions[sid].amount > 0:  
            process_order(sid, 'Sell', context, close)  
        if get_datetime().day == context.day:  
            return  
        context.day = get_datetime().day  
        initalise_context(sid, context)  
        process_order(sid, 'Buy', context, close)

2 responses

Seong Lee

Oct 6, 2014

Hey Andrew,

Essentially, you were passing in 'order' as a parameter into your process_order method which essentially 'overwrites' Quantopian's 'order' method. In order to fix this, you just had to change the 'order' parameter in process_order to a different name:

#: You were passing in order, as a string, which 'overwrites' the 'order' method  
#: so when you were calling order(sid, -number_of_shares), you were essentially trying to do  
#: 'Sell'(sid, -number_of_shares)  
#: I've changed the name around here:  
def process_order(sid, order_name, context, close):  
    cash = context.portfolio.cash  
    context.notional = context.notional + context.portfolio.positions[sid].amount * close  
    datetime = pd.Timestamp(get_datetime()).tz_convert('US/Eastern')  
    if ( order_name.lower()[0][0] == 'b' ):  
        if ( context.notional < context.max_notional ):  
            number_of_shares = int(cash/close)  
            message = '{s}: {o} {n} @ {d}'  
            log.info( message.format( s=sid, o=order, n=number_of_shares, d=datetime ))  
            #order_percent(sid, 0.33, style=MarketOrder(exchange=IBExchange.SMART))  
            order(sid, number_of_shares)  
            context.notional = context.notional + close * number_of_shares  
    else:  
        if ( context.notional > context.min_notional ):  
            number_of_shares = context.portfolio.positions[sid].amount  
            message = '{s}: {o} {n} @ {d}'  
            log.info( message.format( s=sid, o=order, n=number_of_shares, d=datetime ))  
            #order_percent(sid, -0.33, style=MarketOrder(exchange=IBExchange.SMART))  
            order(sid, -number_of_shares)  
            context.notional = context.notional - close * number_of_shares

Seong

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Andrew Leach

Oct 6, 2014

Derrrrh!! Quite obvious now you mention it. Thanks Seong!!

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