Dynamic Y variables in Graph Builder from user selection

Question

Hello,

I’m trying to dynamically control multiple Y axes in Graph Builder based on a user Check Box selection.

Hard-coded Y variables work fine, but any dynamic construction fails (Y unresolved, ignored, or empty plot).

I’ve tried:

Add Variable( Y(...) )

building Expr( Y( ... ) ) lists

Eval / Expr / Column() combinations(as suggested in existing forum threads)

None work for me.

Dynamic number of Y variables (1–4)

Each Y has independent limits / ref lines

Cannot stack data

Must use Graph Builder

// Does NOT work

dt = Open( "$SAMPLE_DATA/Big Class.jmp" );

// Simulate user selection
Chosen_Ys_list = {"height", "weight"};

// Attempt to build Y list dynamically
Y_List = {};
For( i = 1, i <= N Items( Chosen_Ys_list ), i++,
    Insert Into( Y_List, Expr( Y( Eval( Chosen_Ys_list[i] ) ) ) );
);

dt << Graph Builder(
    Variables(
        X( :age ),
        Eval( Y_List )   // <- ignored or errors
    )
);

// 2nd try
gb = dt << Graph Builder(
    Variables( X( :age ) )
);

gb << Add Variable( Y( :height ) );  // Name Unresolved: Y

jthi · Accepted Answer

For << Add Variable you can find the correct syntax from Scripting Index

Not sure what the final plot is supposed to look like, so here is only one simple example using << Add Variable

Names Default To Here(1);

dt = Open("$SAMPLE_DATA/Big Class.jmp");

cols = {"height", "weight"};

gb = dt << Graph Builder(Variables(X(:age)));
For Each({colname}, cols,
	Eval(EvalExpr(
		gb << Add Variable({Expr(Name Expr(AsColumn(dt, colname))), Role("Y")})
	));
);

hogi · Accepted Answer

There is an issue with your Y_List:

besides that, you will run into issues with the "List".

As an alternative to Add Variable (), you can start with a variable_expr, add more variables, and then use it in the Graph Builder command.

Independent of the approach, the correct  positioning  of Eval , Eval Expr, Expr, and NameExpr in the code is essential.
the details can be found in the documentation 
... and in some community posts
https://www.google.com/search?q=expression+handling++site%3Acommunity.jmp.com

Variables_Expr  = Expr(Variables (X(:age)));

For( i = 1, i <= N Items( Chosen_Ys_list ), i++,
    Insert Into( Variables_Expr, Eval Expr( Y( Expr(Name Expr(As Column( Chosen_Ys_list[i] ) ) ) );
)));

Eval (Eval Expr(dt << Graph Builder(
        Expr(Name Expr(( Variables_Expr ) ))    
)));