Referencing a Column by Column Number in Formula in a For loop

Jackieandrews

Hi all,

 

I am trying to generate a bunch of new columns at once using a "for" loop, and each column will get named as the next item in the "sample" matrix. I can figure that part out, I think. But I also want each column to include a formula to look up a different column, which will be different each time, and subtract that value from the initial value (column "0"). When I run this it just gives me formula evaluation errors, not calculating what the column should be that it references.

Thanks for your help!

 

sample = {0, 1, 2, ...}
new columns = N Items (sample);

for( i=1, i<= new columns, i++, col = num(sample [i]);
	
	dt << New Column (sample [i] || " Days",  formula (as column (13+i+new columns) - :Name("0")))
	 	
	 );

txnelson

My error.  The string needs to be parsed to get rid of the pair of quotes

Names Default To Here( 1 );
dt = Current Data Table();
sample = {0, 1, 2};
new columns = N Items( sample );

For( i = 1, i <= new columns, i++,
	col = Num( sample[i] );
	colNamesList = dt << Get Column Names;
	Wait( 0 );
	Eval(
		Substitute(
				Expr(
					dt << New Column( sample[i] || " Days",
						formula( __column__ - :Name( "0" ) )
					)
				),
			Expr( __column__ ),
				Parse(":Name(\!"" || colNamesList[13 + i + new columns] || "\!")")
		)
	);
);