IsValidPlot()

[Stephan123]

Hi,

within the OnBarUpdate()-method I use the following syntax.

Print(Closes[1].IsValidPlot(CurrentBar));
Print(Closes[1][0]);

When the first bar is processed, it puts out true for the first line of the code but gives an error at the second line.

The message:
You are accessing an index with a value that is invalid since its out of range

Does the first line of the syntax not work properly?

[NinjaTrader_RyanM1]

Hi Stephan,

Using the first line does not prevent the script from accessing invalid values. For intended usage of IsValidPlot, see the following link:

http://www.ninjatrader.com/support/helpGuides/nt7/idataseries.htm?zoom_highlightsub=IsValidPlot

You need an appropriate CurrentBars check to ensure you don't attempt to access invalid values. For multseries script, it would be something like this:

if (CurrentBars[1] < 0) return;

[Stephan123]

Hi Stephan,

if (CurrentBars[1] < 0) return;

Thanks, this works fine for checking of the beginning of a bar object.
But how to check for the end of a bar object or a missing bar within a series?

[NinjaTrader_RyanM1]

You may want to look into ContainsValue() for this.

http://www.ninjatrader.com/support/forum/showthread.php?t=33061

[Stephan123]

You may want to look into ContainsValue() for this.

http://www.ninjatrader.com/support/f...ad.php?t=33061

ContainsValue() is for indicator type data only, isn't it?
I have to deal with a secondary chart - a bars object.
I tried Closes[1].IsValidPlot(0) but it also gives false signals. It states true when it's false.

[NinjaTrader_RyanM1]

There needs to be enough data for all series to load, but not sure what function you may need, if any. Can you please post a snippet we can use to see the problem?

[Stephan123]

I have a primary bars object containing a huge history of daily data.
I added a second sereis with

Add(SecondInstrument, BarsPeriods[0].Id, BarsPeriods[0].Value);

SecondInstrument is a string containing "^DAX".

It contains less data history than the primary chart.
History begins later and stops earlier than that of the primary chart.

In OnBarUpdate() the indicator conducts calculations with both instruments
using zero bars ago - values.
To avaoid addressing invalid indices and throwing exceptions I need a command to check for valid entries
to suppress calculations if there is no valid data in the second instrument.

By using

if (CurrentBars[1]<0)
{return;}

I can suppress calculations befor the data history of the second instrument is reached.
It doesn't work if the end of the second instrument is reached.

To check if the data is valid I use
Print(Closes[1][0]);
If it throws an exception it was invalid.
I also print the checking condition (boolean) in the output window to see if it
states what it should do.

I just need something like IsValidPlot() or ContainsValue() in a way that works with
my instrument type data (barsobject).

[NinjaTrader_RyanM1]

Maybe you could do a null check on BarsArray[]?

if (BarsArray[1] == null)

[Stephan123]

Maybe you could do a null check on BarsArray[]?

if (BarsArray[1] == null)

I tried

if (BarsArray[1] == null)
                {return;}
                
Print(BarsArray[1] == null);
Print(Closes[1][0]);

which resulted in a false and an error followed by it.
The error message was:
Error on calling 'OnBarUpdate' method for indicator 'Divergence3' on bar 0: You are accessing an index with a value that is invalid since its out of range.
Seems again like the data validity check doesn't work.

[NinjaTrader_RyanM1]

Thanks for the reply. Sorry, that did not work for you. Unfortunately there isn't a built in method or property to check for this. It must be custom coded. You can work with time stamps possibly, or CurrentBars for each series.

If you only need to solve this one scenario, I would read off the time stamp of the last bar on the secondary series.

[Stephan123]

Thanks, after some hours of trial and error I finally figured something out
using a combination of reading timestamps and CurrentBars values.

[NinjaTrader_RyanM1]

Great - thanks for the update, Stephan.