For Loop Example Requested

[ChainsawDR]

Hi there,

I'm trying to convert a TradingView strategy onto NT8 and struggling to port over a for loop that I'd used - hoping someone may please have an example snippet of a for loop to illustrate how it should be done.

Here's the code I've tried that is throwing an error of "cannot apply indexing with [] to an expression of type 'double'". It's within OnBarUpdate: It is trying to loop through the last 15 bars to see if each bars Close Price meets a variable (myVarOne & myVarTwo), which are and need to be doubles), and essentially counts them (aka how many of the last 15 bars did the close price equal variable X?).

for (int i = 0; i < 15; i++)
{
if (Close[i] == myVarOne[i])
{
//do something
}
if (Close[i] == myVarTwo[i])
{
//do something
}

I've also tried a foreach but no joy. This may be a C# general coding question and if so will research further, but as been at it for 90mins+ already I'm hoping to understand how others implement their loops through price bars.

Many thanks in advance

ChainsawDR

[s.kinra]

Hello ChainsawDR,
It seems you're missing parenthesis of for loop, consider below code:

for (int i = 0; i < 15; i++)
{
if (Close[i] == myVarOne[i])[INDENT]{
//do something
}[/INDENT]
  if (Close[i] == myVarTwo[i])[INDENT]{
//do something
}[/INDENT]
 }

Be sure myVarOne & myVarTwo are double series (not just double variables). When you need to use these as double you can call them as myVarOne[0] & myVarTwo[0].
Hope it helps!

[bltdavid]

I'm trying to convert a TradingView strategy onto NT8 and struggling to port over a for loop that I'd used - hoping someone may please have an example snippet of a for loop to illustrate how it should be done.

Here's the code I've tried that is throwing an error of "cannot apply indexing with [] to an expression of type 'double'". It's within OnBarUpdate: It is trying to loop through the last 15 bars to see if each bars Close Price meets a variable (myVarOne & myVarTwo), which are and need to be doubles), and essentially counts them (aka how many of the last 15 bars did the close price equal variable X?).

for (int i = 0; i < 15; i++)
{
if (Close[i] == myVarOne[B][COLOR=#e74c3c][i][/COLOR][/B])
{
//do something
}
if (Close[i] == myVarTwo[B][COLOR=#e74c3c][i][/COLOR][/B])
{
//do something
}

I've also tried a foreach but no joy. This may be a C# general coding question and if so will research further, but as been at it for 90mins+ already I'm hoping to understand how others implement their loops through price bars.

Your loop is fine, that's not the problem.

If myVarOne and myVarTwo are simple double variables, like you say,
then don't append the suffix '[i]' -- that makes the compiler think the
variable is something with an index -- like an array, or a list, or a Series.

Remove that '[i]' and you should be fine.
Why? Because a simple double variable does not have an index.

Also, sit down and study the compiler error message. It is spot-on,
drop-dead 100% accurate and completely precise. It is worded
exactly, and absolutely describes your problem -- make sure you
embody the lesson of that error message -- the message says
'expression' but it's referrng to myVarOne and myVarTwo.

[ChainsawDR]

Thank you both for helping put me on the right path, much appreciated!

[ChainsawDR]

In case others run up against a similar issue in future, this was resolved by:

//Adding the series in the intro public class section:
private Series<double> myVarOne;
private Series<double> myVarTwo;

//adding the series within State.DataLoaded - aka at this point its empty, its just been initiated to be used later:
myVarOne = new Series<double>(this, MaximumBarsLookBack.TwoHundredFiftySix);
myVarTwo = new Series<double>(this, MaximumBarsLookBack.TwoHundredFiftySix);

//Finally within OnBarUpdate, any Adds TO the series, or Reading FROM the series need to have the index specified, e.g.:

myVarOne[0] = Close[0] //adds the close price to this variable

Thank you again s.kinra & bltdavid for the guidance!

ChainsawDR