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Difference between FOR and FOR EACH loops

Can somebody explain why this:

dt = Open( "$SAMPLE_DATA/Fitness.jmp" );
col = { :Runtime, :RunPulse, :RstPulse };

y expr  = Expr( Y() );
For( c = 1, c <= N Items( col ), c++,
 Insert Into( y expr, col[c] );
);

Name Expr(y expr);

produces expected output

Y( :Runtime, :RunPulse, :RstPulse )

but this:

dt = Open( "$SAMPLE_DATA/Fitness.jmp" );
col = { :Runtime, :RunPulse, :RstPulse };

y expr  = Expr( Y() );
For each({coll, index},col,
 Insert Into( y expr, coll );
);

Name Expr(y expr);

produces this:

Y( ., ., . )

I would expect it to give the same result? How should I change FOR EACH loop to give the same result?

 

 

ScriptingRe: Difference between FOR and FOR EACH loops

My guess is that the columns get evaluated into current rows values in For Each (you can test this by adding Row() = 1; for example). You might be able to avoid this by using Name Expr()

Names Default To Here(1);

dt = Open("$SAMPLE_DATA/Fitness.jmp");
col = {:Runtime, :RunPulse, :RstPulse};

y expr = Expr(Y());
For(c = 1, c <= N Items(col), c++,
 Insert Into(y expr, col[c]);
);
Show(Name Expr(y expr));

Row() = 1;
y expr = Expr(Y());
For Each({coll, index}, col, 
 Insert Into(y expr, coll);
);
Show(Name Expr(y expr));

y expr = Expr(Y());
For Each({coll, index}, col, 
 Insert Into(y expr, Name Expr(coll));
);
Show(Name Expr(y expr));

Re: Difference between FOR and FOR EACH loops

Yes, this is it.

It is a strange behavior, since 1. we have For Each Row statement for by row evaluation, and 2. For Each should treat a list (and I'm trying to work with a list of references to columns) same as For loop.

Is this a bug or is it intended behavior?