Creating new columns with a For loop and giving each column its own name and formula

[#1]

Hello everyone,

I have a large data table with values and column headers test1,test2,test3,test4,...,test800. Some of these values are negative, and I would like to take all the columns I define in the list "Datalist_log_2" and create a new column called "test1_pos" with the absolute values. (For each test).

Datalist_log_2 = {test1, test2, test5, test319};
wmax = N Items( Datalist_log_2 );

For ( w = 1, w <=wmax, w++,
	Temp12 = Char(Datalist_log_2[w]);
	NewColName = Temp12||"_pos";	//not sure if I need to do this extra round, but it works. Will figure that out myself.
	NewColumn(NewColName, Numeric, Continuous, Formula(Abs(Datalist_log_2[w]))) 
);

The problem seems to be that the Formula() is trying to build the absolute value of the variable "test1" in the first iteration, but of course I don't want sqrt(test1*test1). Instead I would like the newly created column to get the absolute values of the reference column with the name "test1".

Thanks a lot for your help

[#2]

How timely, check out this JSL Cookbook article which does something very similar.  Just specify your own list of columns to change, then modify the new column name and formula.

I suggest selecting the columns and using the Current Data Table() << Get Selected Columns message to write the list to the log, which you can then copy and paste into your code.

[#3 · Accepted solution]

Below is a modification of your current code, using the same methodology as I passed to you in your previous post "Combining For loop and Dispatch() command in a variability chart" .  If you are not able to interpret what is going on, I suggest that you take a look in the Scripting Guide for explanation.

     Help==>Books==>Scripting Guide

Datalist_log_2 = {test1, test2, test3};

For( w = 1, w <= N Items( Datalist_log_2 ), w++,
	Eval(
		Substitute(
				Expr(
					New Column( Char( Datalist_log_2[w] ) || "_pos",
						Numeric,
						Continuous,
						Formula( Abs( __Col__ ) )
					)
				),
			Expr( __col__ ), Parse( ":" || Char( Datalist_log_2[w] ) )
		)
	)
);

[#4]

This works great, thanks