3. How to write size into self.mystats.write
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How to write size into self.mystats.write

  • V

    Hello guys,
    anyone can help me? I try to write the size of trade while next().
    My understanding is that first define self.tradesize in notify_trade:

    def notify_trade(self, trade):
        if trade.justopened:
            self.tradesize = trade.size

    Then, I try to calculate the trade in next():

            if self.tradesize:
            self.tsize = self.tradesize[0]
        else:
            self.tsize = 0

    I get the error: "AttributeError: 'Lines_LineSeries_LineIterator_DataAccessor_Strateg' object has no attribute 'tradesize'"

    What do I do wrong?

    Many thanks,
    Vaclav

    0
  • A

    self.tradesize as it is calculated in the notify_trade() is a number. So I don't think that self.tradesize[0] is a valid call. Otherwise I don't see any other issues with the piece of code above. Also it is better to provide full error message since python shows lines of code which causes the error.

    1
  • V

    Hello, thanks for support. To be honest, I don't want leave the topic without a clue not meet the issue in future.
    When I log the self.tradesize in notify_trade, it works well.
    However, I understand the issue in the way, the instance of class does not know the (self.)tradesize.

      File "C:\UsersXXX\___master\master.py", line 137, in runstrat
    cebrun = cerebro.run()
  File "C:\UsersXXX\lib\site-packages\backtrader\cerebro.py", line 1127, in run
    runstrat = self.runstrategies(iterstrat)
  File "C:\UsersXXX\lib\site-packages\backtrader\cerebro.py", line 1293, in runstrategies
    self._runonce(runstrats)
  File "C:\UsersXXX\lib\site-packages\backtrader\cerebro.py", line 1695, in _runonce
    strat._oncepost(dt0)
  File "C:\UsersXXX\lib\site-packages\backtrader\strategy.py", line 311, in _oncepost
    self.nextstart()  # only called for the 1st value
  File "C:\UsersXXX\lib\site-packages\backtrader\lineiterator.py", line 347, in nextstart
    self.next()
  File "C:\UsersXXX\___master\modules\strategy.py", line 149, in next
    if self.tradesize:
  File "C:\UsersXXX\lib\site-packages\backtrader\lineseries.py", line 461, in __getattr__
    return getattr(self.lines, name)
AttributeError: 'Lines_LineSeries_LineIterator_DataAccessor_Strateg' object has no attribute 'tradesize'

    Please, note: I try it without the index as well.

            if self.tradesize:
            self.tsize = self.tradesize
        else:
            self.tsize = 0

    Line 149 refers to the condition...
    Thank you for your time.

    0
  • V

    @ab_trader : I've also tried make it in init

    self.tsize = bt.If(self.tradesize, self.tradesize, 0)

    The issue is almost the same.

    This however works well:

        def notify_trade(self, trade):
        if trade.justopened:
            print('----TRADE OPENED----')
            self.tradesize = trade.size
            print(self.tradesize)

    And prints the size...

    0
  • A

    Put self.tradesize = None or self.tradesize = 0 in the __init()__. It is undefined for first next() calls before you get your trade open.

    3
  • V

    @ab_trader : Many thanks. A new added value for me. Very appreciated.

    0
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