Generic way to get len() of data feed?

[josipbt]

Is there a generic way to get the len(), if I don't pass the whole pandas DataFrame to cerebro?

In my case I did it like this:

df = pd.read_csv(
    'ticks.csv',
    header=0,
    parse_dates=[0],   
    date_parser=lambda x: datetime.datetime.fromtimestamp(int(x)/1000)
    )
    
todate = datetime.datetime(2021, 5, 28,22,00)
datalen = len(df[df["timestamp"] < todate])
   
data = bt.feeds.PandasData(
    dataname=df,
    fromdate=datetime.datetime(2000, 1, 1),
    todate=todate,
    timeframe=bt.TimeFrame.Ticks
    datetime=0,
    high=9,
    low=10,
    open=7,
    close=8,
    volume=11,
    )

Overall, my goal is to have a simple progress bar/indicator. This solution was a bit more than I actually needed.

Any hints are more than welcome.