Cerebro.run() Type Error

[Darshil Shah]

Hello Guys,
I am new to this community and have just started using backtrader. I have written a piece of code but whenever i use the cerebro.run(), It shows TypeError: must be real number, not LineBuffer. Attaching my piece of code for reference. It would be great if you could help. Thank you

from future import (absolute_import, division, print_function,
unicode_literals)
import backtrader as bt
import backtrader.indicators as btind
import datetime
import os.path
import sys

class Sentiment(bt.Indicator):
lines = ('sentiment',)
plotinfo = dict(
plotymargin=0.15,
plothlines=[0],
plotyticks=[1.0, 0, -1.0])

def next(self):
    self.date = self.data.datetime
    date = bt.num2date(self.date[0]).date()
    prev_sentiment = self.sentiment
    if date in date_sentiment:
        self.sentiment = date_sentiment[date]
    self.lines.sentiment[0] = self.sentiment

class SentimentStrat(bt.Strategy):
params = (
('period', 15),
('printlog', True),
)

def log(self, txt, dt=None, doprint=False):
    ''' Logging function for this strategy'''
    if self.params.printlog or doprint:
        dt = dt or self.datas[0].datetime.date(0)
        print('%s, %s' % (dt.isoformat(), txt))

def __init__(self):
    # Keep a reference to the "close" line in the data[0] dataseries
    self.dataclose = self.datas[0].close
    # Keep track of pending orders
    self.order = None
    self.buyprice = None
    self.buycomm = None
    self.sma = bt.indicators.SimpleMovingAverage(
        self.datas[0], period=self.params.period)
    self.date = self.data.datetime
    self.sentiment = None
    Sentiment(self.data)
    
def notify_order(self, order):
    if order.status in [order.Submitted, order.Accepted]:
        # Buy/Sell order submitted/accepted to/by broker - Nothing to do
        return
    
    # Check if an order has been completed
    # Attention: broker could reject order if not enough cash
    if order.status in [order.Completed]:
        if order.isbuy():
            self.log(
                'BUY EXECUTED, Price: %.2f, Cost: %.2f, Comm %.2f' %
                (order.executed.price,
                 order.executed.value,
                 order.executed.comm))
            self.buyprice = order.executed.price
            self.buycomm = order.executed.comm
        else:  # Sell
            self.log('SELL EXECUTED, Price: %.2f, Cost: %.2f, Comm %.2f' %
                     (order.executed.price,
                      order.executed.value,
                      order.executed.comm))
            
        self.bar_executed = len(self)     
        
    elif order.status in [order.Canceled, order.Margin, order.Rejected]:
        self.log('Order Canceled/Margin/Rejected')
        
    # Write down: no pending order
    self.order = None
    
def notify_trade(self, trade):
    if not trade.isclosed:
        return

    self.log('OPERATION PROFIT, GROSS %.2f, NET %.2f' %
             (trade.pnl, trade.pnlcomm))

### Main Strat ###
def next(self):
    # log closing price of the series from the reference
    self.log('Close, %.2f' % self.dataclose[0])
    
    date = bt.num2date(self.date[0]).date()
    prev_sentiment = self.sentiment
    if date in date_sentiment:
        self.sentiment = date_sentiment[date]
    
    # Check if an order is pending. if yes, we cannot send a 2nd one
    if self.order:
        return
    print(self.sentiment)
    # If not in the market and previous sentiment not none
    if not self.position and prev_sentiment:
        # buy if current close more than sma AND sentiment increased by >= 0.5
        if self.dataclose[0] > self.sma[0] and self.sentiment - prev_sentiment >= 0.5:
            self.log('BUY CREATE, %.2f' % self.dataclose[0])
            self.order = self.buy()
            
    # Already in the market and previous sentiment not none
    elif prev_sentiment:
        # sell if current close less than sma AND sentiment decreased by >= 0.5
        if self.dataclose[0] < self.sma[0] and self.sentiment - prev_sentiment <= -0.5:
            self.log('SELL CREATE, %.2f' % self.dataclose[0])
            self.order = self.sell()

def stop(self):
    self.log('(MA Period %2d) Ending Value %.2f' %
             (self.params.period, self.broker.getvalue()), doprint=True)

if name == 'main':
cerebro = bt.Cerebro()

# Strategy
cerebro.addstrategy(SentimentStrat)

# Data Feed
data = bt.feeds.YahooFinanceCSVData(
    dataname = r'C:\Users\HP\Downloads\AMZN.csv',
    fromdate = earliest_date,
    todate = datetime.datetime(2019,6,19),
    reverse = False
)

cerebro.adddata(data)

cerebro.broker.setcash(100000.0)
cerebro.addsizer(bt.sizers.FixedSize, stake=10)
cerebro.broker.setcommission(commission=0.001)
print('Starting Portfolio Value: %.2f' % cerebro.broker.getvalue())
cerebro.run()
print('Final Portfolio Value: %.2f' % cerebro.broker.getvalue())

cerebro.plot()

[backtrader]

@Darshil-Shah said in Cerebro.run() Type Error:

I am new to this community and have just started using backtrader.

Basics

• Rule #1 when playing chess and doing algotrading: look at what you have before your nose
• Rule #2: go always back to Rule #1

As such (and the top of each and every page in the forum)

For code/output blocks: Use ``` (aka backtick or grave accent) in a single line before and after the block. See: http://commonmark.org/help/

Without that your code is basically unreadable for human beings with two eyes (those with three may possible add an extra visual dimension and put the code back together)

There are a couple of obvious things in any case:

@Darshil-Shah said in Cerebro.run() Type Error:

It shows TypeError: must be real number, not LineBuffer

• Haven't you considered that sharing the error (the trace) is as important as the code?

  This is telling you, that you are passing the line to an assigment, where you should be passing a float (or something which can be converted directly to a float like an int

@Darshil-Shah said in Cerebro.run() Type Error:

    if date in date_sentiment:
        self.sentiment = date_sentiment[date]

That code at the beginning is obviously doomed to fail, because there is no date_sentiment defined anywhere even if the code is unreadable.

@Darshil-Shah said in Cerebro.run() Type Error:

    self.date = self.data.datetime
    date = bt.num2date(self.date[0]).date()

A lot easier (and timezone aware if timezones are used) if you do:

date = self.data.datetime.date()