Variables region - "for" loop

[Shansen]

All,

Is it possible to use a "for" loop in the variables region to define multple variables. For example:

for (int i=0; i<3; i++)
{
  private int ("CurrentBar" + i.ToString());
  private int ("CurrentPeak" + i.ToString());
}

To produce six variables:
CurrentBar0
CurrentPeak0
CurrentBar1
CurrentPeak1
CurrentBar2
CurrentPeak2

Regards
Shannon

[NinjaTrader_Austin]

Shansen, from what I recall, creating variables in the Initialize() section programmatically isn't supported.

I'm not sure it even works... does your code correctly initialize the variables? Can you access the variables later on?

[Shansen]

Austin,

Thank you for the quick reply.

The loop structure is intended to rest in the variables region ( not the initialize section ).
I think the issue could revolve around my joining of two strings as the variable name.
Any assistance would be appreciated.

Thanks again
Shannon

[Ralph]

Hi Shannon,

what you are trying to do is not possible with a compiler language like c# (perhaps with a interpreter language like tcl/tk?). A for-loop is a construct to be executed during runtime. But a variable has to be recognised by the compiler during compile time. To group variables you could use arrays:

int CurrentBar[3];
int CurrentPeak[3];
...
CurrentBar[0] = 42;
CurrentPeak[0] = 84;

Regards
Ralph

[Shansen]

Ralph,

Thanks for the reply. Bummer it can't be done.

Elsewhere in in the NT Strategy code I do use ArrayLists.

This request was aimed at reducing some of repetitive nature of defining and parsing values to the strategy from one indicator that is run on four different time-frames. Once the parsed values are assigned to variable in the strategy, they are evaluated.

Gauging from your reply, would it be possible to separately define variables:

#region Variables
  private int CurrentBar0;
  private int CurrentPeak0;
  private int CurrentBar1;
  private int CurrentPeak1;
  private int CurrentBar2;
  private int CurrentPeak2;
  etc...
#endregion

And then work with these variables and a "looped" fashion:

protected override void OnBarUpdate()
{
  for (int i=0; i<3; 1++)
  {  
    if (BarsInProgress == i && FirstTickOfBar)
    {
      ("CurrentBar" + i.ToString()) = indicator value;
      ("CurrentPeak" + i.ToString()) = indicator value;
    }
  }
  ...
  ...
  ...
}

If this is possible what syntax should be used to join the strings to form the variable name?

As always, thanks a bunch
Shannon

[Ralph]

You should swap the lines for(int...) and if(BarsInProgress...), otherwhise you waste cpu resources just for nothing with every invocation of OnBarUpdate().

How do you fill variable "indicator value"? Is it a fixed value by source code, or set by a public property, or ...?

Regards
Ralph

[Shansen]

Ralph,

Apologies, I have amended the code in the prior post to reflect my intentions. Within the loop structure the test should be BarsInProgress == i.

The indicator value are either public DataSeries or public IntSeries. Does this impact your response? And importantly, will the syntax ("CurrentBar" + i.ToString()) have the expected results?

Thanks again
Shannon

[Ralph]

Hi Shannon,

For some reason I missed your concept of BarsInProgres. Suspect I was still sleeping while typing this morning.

You can't neither construct a variable during runtime nor can't you construct a reference to a variable during runtime. That may be possible with an interpreter language but not with a compiler language. But that does not make sense anyway, c# provides you with different containers for efficient data storage instead of dealing with expensive string operations during runtime. But I think for your application a simple array is the best choice, the dimension has to be the number of time frames used. Here is a second attempt:

private int CurrentBar[4];
private int CurrentPeak[4];
 
protected override void OnBarUpdate()
{
  if (FirstTickOfBar)
  {
    if (BarsInProgress >= 0 && BarsInProgress <=3)
    {
      CurrentBar[BarsInProgress] = indicator value;
      CurrentPeak[BarsInProgress] = indicator value;
    }
    else
    {
      Print("Unexpected value for BarsInProgress: " + BarsInProgress);
      Log("Unexpected value for BarsInProgress: " + BarsInProgress);
    }
  }
  ...
  ...
  ...
}

I was asking for the "indicator value" because it is possible to fill an array during variable initialisation. But that's not your intention obviously.

Regards
Ralf

[Shansen]

Ralph,

Thanks for help. I'm pretty sure that would have never crossed my mind.

In implementing:

#region Variables
  private int[] CurrentBars;
  private int[] CurrentPeak;
#endregion

protected override void Initialize()
{
  CurrentBars = new int[4];
  CurrentPeak = new int[4];

  for (int x = 0; x < 4; x++)
  {
    CurrentBars[x] = 0;
    CurrentPeak[x] = 0;
  }
}

protected override void OnBarUpdate()
{
  if (FirstTickOfBar)
  {
    if (BarsInProgress >= 0 && BarsInProgress <= 3) 
    {
      Print (BarsInProgress + " - " + Times[BarsInProgress][0].ToString());
      CurrentBars[BarsInProgress] = CurrentBar;
      CurrentPeak[BarsInProgress] = Indicator.Property[1];
    }
    else
    {
      Print("Unexpected value for BarsInProgress: " + BarsInProgress);
    }
  }
}

The Log shows an error-> Error on calling 'OnBarUpdate' ...: Index was out of range. Must be non-negative and less than the size of the collection Parameter name: index

The four time frames are in order of BarArray:
0 - 15min futures
1 - 5min cash
2 - 5min futures
3 - 1min futures

I could be off-track trying to debug this issue, but I'm pretty sure these BarArrays should not present a problem in their current descending order.

As always any assistance would be appreciated.

Regards
Shannon

[Ralph]

Hi Shannon,

you do not need to initialise your arrays with zero. C# promises that this is done during construction.
Cannot see an issue either. Do your print statements work? Guess that would allow a conclusion.

Regards
Ralph