Time[0] returns the datetime of the oldest bar in the playback chart

[Red_70]

I'm running a simple strategy in playback mode that includes the line

Print(Time[0].ToString());

but it prints the datetime value of the oldest bar in the chart instead of the current bar's datetime.

How do I obtain the current bar's datetime in playback mode?

[NinjaTrader_BrandonH]

Hello Red_70,

Thanks for your post.

Time[0] would return the time of the current bar on a chart when using Playback with Market Replay data.

See this demonstration video: https://brandonh-ninjatrader.tinytak...N18yMzAzOTMyOQ

Time: https://ninjatrader.com/support/help...eries_time.htm
Playback: https://ninjatrader.com/support/help...connection.htm

[Red_70]

Hi Brandon,

My OnBarUpdate block consists of only two lines:

Print("Time[0] = " + Time[0]);
Print("Time[1] = " + Time[1]);

This should print the datetime values of the current bar and the previous bar (2024-03-28 10:23:00 and 2024-03-28 10:22:00) but instead it prints 3/23/2024 8:05:00 AM for the first value and then throws an error for the second value.

Here's a screenshot of what I'm experiencing:




Am I missing something obvious here?

[bltdavid]

Am I missing something obvious here?

Yes.

On the very first bar, the previous bar does not exist.

The attempt to access Time[1] on the very first bar
fails, because anything with BarsAgo index [1] doesn't
exist yet when there is only 1 bar.

Just like anything using BarsAgo index [100] fails
until you have 101 bars.

Make sense?

-=o=-

"Throwing an error for the second" is expected behavior,
because your code is wrong.

That is, your code has a bug.

-=o=-

How to avoid this error?

Easy.

Use some guard code, something like this,

if (CurrentBar < 1)
    return;

Print("Time[0] = " + Time[0]);
Print("Time[1] = " + Time[1]);​

This kind of guard code is very common at the top of
OnBarUpdate.

Good reading here.

[NinjaTrader_BrandonH]

Hello Red_70,

Thanks for your notes.

bltdavid is correct and has provided some excellent information on this topic.

This error message indicates that you are trying to access a BarsAgo value that is not valid.

A more simple example using one series would be on bar 5 you check for 6 BarsAgo. There are not yet 6 bars so the CurrentBar minus 6 would be a negative number or a non-existent bar.

A CurrentBar check could be used in your indicator's logic to ensure that a certain number of bars have processed before the indicator begins calculation.

See the help guide documentation below for more information.

CurrentBar - https://ninjatrader.com/support/help...currentbar.htm
Make sure you have enough bars - https://ninjatrader.com/support/help...nough_bars.htm

[Red_70]

Hi bitdavid and Brandon,

Thanks for your responses. My misunderstanding here was that OnBarUpdate() would apply only to the current bar, and not to every bar on the chart. Now all is clear!