AttributeError: 'NoneType' object has no attribute 'close'

Maxim Korobov

What's reason that f is None?

"version": "1.9.47.116"
backtrader\feed.py

...

def preload(self):
    while self.load():
        pass

    self._last()
    self.home()

    # preloaded - no need to keep the object around - breaks multip in 3.x
    self.f.close()
    self.f = None

...

Traceback (most recent call last):
  File "D:/Projects/trading-bot/main/lab/backtrader/playground.py", line 277, in <module>
	run()
  File "D:/Projects/trading-bot/main/lab/backtrader/playground.py", line 119, in run
	strategies = run_strategy(back_trader, run_mode == RunMode.DevelopIdea, from_date, to_date)
  File "D:/Projects/trading-bot/main/lab/backtrader/playground.py", line 218, in run_strategy
	strategies = back_trader.run()
  File "C:\Users\Home\Anaconda3\lib\site-packages\backtrader\cerebro.py", line 1070, in run
	runstrat = self.runstrategies(iterstrat)
  File "C:\Users\Home\Anaconda3\lib\site-packages\backtrader\cerebro.py", line 1146, in runstrategies
	data.preload()
  File "C:\Users\Home\Anaconda3\lib\site-packages\backtrader\feed.py", line 689, in preload
	self.f.close()
AttributeError: 'NoneType' object has no attribute 'close'

Maxim Korobov

Possible due to this :)

https://ichart.yahoo.com/table.csv?s=NFLX&a=0&b=1&c=2016&d=4&e=16&f=2017&g=h&ignore=.csv

alt text

Zubin Bharucha

@Maxim-Korobov I was going crazy with the same error. Thanks for this post!

Zubin Bharucha

@backtrader, is there any news/update on this issue? Thanks in advance.

backtrader

It's not a platform issue (aside from better handling the error). It's a Yahoo issue or it may simply be that Yahoo has decided to pull the plug and no longer offer unrestricted/unauthenticated csv downloads.

rorymack

Maxim

I am getting the same type of error running anything that tries to pick up a Yahoo feed.

Traceback (most recent call last):
  File "btfd.py", line 233, in <module>
    runstrat()
  File "btfd.py", line 177, in runstrat
    cerebro.run(**eval('dict(' + args.cerebro + ')'))
  File "/Users/rorymackay/anaconda/envs/backtrader/lib/python2.7/site-packages/backtrader/cerebro.py", line 1070, in run
    runstrat = self.runstrategies(iterstrat)
  File "/Users/rorymackay/anaconda/envs/backtrader/lib/python2.7/site-packages/backtrader/cerebro.py", line 1146, in runstrategies
    data.preload()
  File "/Users/rorymackay/anaconda/envs/backtrader/lib/python2.7/site-packages/backtrader/feed.py", line 689, in preload
    self.f.close()
AttributeError: 'NoneType' object has no attribute 'close'

I assume it is for the same reason, earlier I had an error message that pointed directly to the url you showed.

However using pandas and accessing the same data (perhaps not in the same way ) I do get a response.
I did have to directly install the pandas-Datareader from pip as the anaconda one was not working. (this on a linux box)
Conda appears to have fixed this as the "latest" version is working on a mac...

pandas-datareader         0.3.0.post0              py27_0    conda-forge

This is the pip version that is now working on the linux box.

Not sure if that sheds any light on the issue.

this gets the data to a csv ...



import datetime
import numpy as np
import pandas as pd
#import pandas_datareader as pdr
import pandas_datareader.data as web
import os 
import sys  # To find out the script name (in argv[0])
start = datetime.datetime(2000, 1, 1)
end = datetime.datetime(2015, 5, 9)

data = web.DataReader('ORCL', 'google',start,end)

os.chdir('/Users/rorymackay/Documents/backtrader_test')
modpath = os.path.dirname(os.path.abspath(sys.argv[0]))
datapath = os.path.join(modpath,'backtrader_test/datas/orcl.csv')

data.to_csv('orcl.csv')

Maxim Korobov

What about implementing Quandl data source internally.
One cons is that API key is mandatory.

backtrader

It would be down to each user to have a key. Something to consider.

backtrader

There is a native Quandl data feed (for the WIKI Data) starting with 1.9.48.116

backtrader

Yahoo has apparently discontinued the service (without major notice).

Yahoo Forums: https://forums.yahoo.net/t5/Yahoo-Finance-help/Is-Yahoo-Finance-API-broken/td-p/250503/page/3
Stack Overflow: http://stackoverflow.com/a/44046477/5642219 (points to yahoo, not likely to be deleted, like the above may be)

See this note for the updated Yahoo data feed: Docs - Yahoo Data Feed Notes

Trisspah

Hi,
Since this Yahoo service discontinuation, I'm having problems with some symbols, which all happen to be traded in Paris.

I did update backtrader, and moved to the correct new syntax (unless I'm mistaken).

This works: data = bt.feeds.YahooFinanceData(dataname='GOOG', fromdate=datetime.datetime(2016, 1, 1), todate=datetime.datetime(2017, 05, 15))

This doesn't work anymore: data = bt.feeds.YahooFinanceData(dataname='KN.PA', fromdate=datetime.datetime(2016, 1, 1), todate=datetime.datetime(2017, 05, 15))

I'm getting an error when trying to run the strategy (which didn't change and used to work).

Here's the trace I get:

File "C:\Python\27\lib\site-packages\backtrader\cerebro.py", line 1070, in run
    runstrat = self.runstrategies(iterstrat)
  File "C:\Python\27\lib\site-packages\backtrader\cerebro.py", line 1146, in runstrategies
    data.preload()
  File "C:\Python\27\lib\site-packages\backtrader\feed.py", line 682, in preload
    while self.load():
  File "C:\Python\27\lib\site-packages\backtrader\feed.py", line 476, in load
    _loadret = self._load()
  File "C:\Python\27\lib\site-packages\backtrader\feed.py", line 704, in _load
    return self._loadline(linetokens)
  File "C:\Python\27\lib\site-packages\backtrader\feeds\yahoo.py", line 110, in _loadline
    o = float(linetokens[next(i)])
ValueError: could not convert string to float: null

I assume fetching the data fails and the strategy runs on no data.

Am I missing something?

backtrader

See here: Community - Error in cerebro.run() when getting data with YahooFinanceData (new API)

Trisspah

@backtrader My bad, thanks :)

backtrader

See the news release, Community - Release 1.9.50.117 and this note Community - YahooFinace Data Feeds