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Expression Not Evaluating.

Always mystified by how to use Eval Expr correctly.  I have this pop up that asks for a wildcard column name selection and assigns it as "Divider"

nw = New Window( "Does the Data Contain Experimental Cells?",
	<<MODAL></MODAL>

I then try to evaluate the object in a column formula and whatever combination of Eval(Eval Expr( I use, nothing seems to work.

If( N Items( yVars ) == 0,
	Data Table( "HIRP" ) << New Column( "Average Active Power",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Formula(
			If(
				:Heater == "Reader", Col Mean( :HL_R_HEAT, :Heater ),
				Contains( :Heater, "Writer" ),
					Col Mean( :HL_W_HEAT, :Heater )
			)
		)
	),
	Eval(Eval Expr(Data Table( "HIRP" ) << New Column( "Average Active Power",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Formula(
			If(
				:Heater == "Reader", Col Mean( :HL_R_HEAT, :Heater, As Column(Expr(Divider)) ),
				Contains( :Heater, "Writer" ),
					Col Mean( :HL_W_HEAT, :Heater, :HD_NUM, As Column(Expr(Divider)) )
			)
		)
	)
)));

 

 

 

 

 

Automation and ScriptingRe: Expression Not Evaluating.

Change

As Column(Expr(Divider))

To

Expr(NameExpr(As Column(dt, Divider)))

Name Expr() isn't necessary but you will end up with "nicer looking" formulas when you use that.

Names Default To Here(1); 

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

div = "weight";
Eval(EvalExpr(
	dt << New Column("C", Numeric, Continuous, Formula(
		:Height / Expr(NameExpr(AsColumn(dt, div)))
	))
));

Also, you can test your expression evaluations by just running the EvalExpr part instead of the whole Eval(EvalExpr(...

Re: Expression Not Evaluating.

Needed a small tweak but worked, Thanks

If( N Items( yVars ) == 0,
	Data Table( "HIRP" ) << New Column( "Average Active Power",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Formula(
			If(
				:Heater == "Reader", Col Mean( :HL_R_HEAT, :Heater ),
				Contains( :Heater, "Writer" ),
					Col Mean( :HL_W_HEAT, :Heater )
			)
		)
	),
	Eval(Eval Expr(Data Table( "HIRP" ) << New Column( "Average Active Power",
		Numeric,
		"Continuous",
		Format( "Best", 12 ),
		Formula(
			If(
				:Heater == "Reader", Col Mean( :HL_R_HEAT, :Heater, Expr(NameExpr(As Column( Divider))) ),
				Contains( :Heater, "Writer" ),
					Col Mean( :HL_W_HEAT, :Heater, :HD_NUM, Expr(NameExpr(As Column( Divider))) )
			)
		)
	)
)));

Re: Expression Not Evaluating.

Jarmo

 

I have something that works now but I don't understand why it works.  Is there somewhere that gives a clear description of how the evaluation methodology should be employed?  Hoping to spend less time on here searching for answers.

Re: Expression Not Evaluating.

Session 9: Advanced JSL 

Scripting Guide > Programming Methods > Advanced Expressions, Macros, and Lists 

Morgan, J. (2010). “Expression Handling Functions: Part I.” JMPer Cable 26:15–19.