Plotting of resample data

[vaclavku]

dear all, I try to plot the original and resampled data, however there's the following issue:

Traceback (most recent call last):
  File "_initial.py", line 158, in <module>
    scan()
  File "_initial.py", line 120, in scan
    fcommission
  File "C:\Users\XXX\master.py", line 258, in runstrat
    cerebro.plot(style='candlestick')
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\backtrader\cerebro.py", line 991, in plot
    start=start, end=end, use=use)
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\backtrader\plot\plot.py", line 189, in plot
    self.plotind(None, ptop, subinds=self.dplotsover[ptop])
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\backtrader\plot\plot.py", line 472, in plotind
    plottedline = pltmethod(xdata, lplotarray, **plotkwargs)
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\matplotlib\axes\_axes.py", line 1666, in plot
    lines = [*self._get_lines(*args, data=data, **kwargs)]
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\matplotlib\axes\_base.py", line 225, in __call__
    yield from self._plot_args(this, kwargs)
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\matplotlib\axes\_base.py", line 391, in _plot_args
    x, y = self._xy_from_xy(x, y)
  File "C:\Users\XXX\Local\Programs\Python\Python37\lib\site-packages\matplotlib\axes\_base.py", line 270, in _xy_from_xy
    "have shapes {} and {}".format(x.shape, y.shape))
ValueError: x and y must have same first dimension, but have shapes (690,) and (689,)

The code of the resample is:

    namedf = tic
    df = pd.read_sql(namedf, conn)

    data0 = bt.feeds.PandasData(dataname=df, 
                               timeframe=bt.TimeFrame.Minutes,
                               compression=1)#, fromdate=start, todate=end)
    cerebro.adddata(data0)

    data1 = bt.feeds.PandasData(dataname=df, 
                               timeframe=bt.TimeFrame.Minutes,
                               compression=1)
    
    cerebro.resampledata(data1, timeframe = bt.TimeFrame.Minutes, compression = 60) 

The resampling itself as well as plotting work well.

Many thanks.

[backtrader]

Yes, that's something which happens on some scenario when mixing different timeframes. matplotlib is not forgiving at all when putting things on the same axis is something is slightly misaligned.

@vaclavku said in Plotting of resample data:

    data0 = bt.feeds.PandasData(dataname=df, 
                               timeframe=bt.TimeFrame.Minutes,
                               compression=1)#, fromdate=start, todate=end)
    cerebro.adddata(data0)

    data1 = bt.feeds.PandasData(dataname=df, 
                               timeframe=bt.TimeFrame.Minutes,
                               compression=1)
    
    cerebro.resampledata(data1, timeframe = bt.TimeFrame.Minutes, compression = 60) 

Although it won't cure the issue, you can actually do this

    data0 = bt.feeds.PandasData(dataname=df, 
                               timeframe=bt.TimeFrame.Minutes,
                               compression=1)#, fromdate=start, todate=end)
    cerebro.adddata(data0) 
    cerebro.resampledata(data0, timeframe = bt.TimeFrame.Minutes, compression = 60) 

[vaclavku]

Many thanks for confirming.