topic Stack column using table variable list in Discussions

Stack column using table variable list

snapnpop — Wed, 06 Feb 2019 14:43:57 GMT

I would like to stack a list of columns based on a table variable, but I'm having trouble figuring out how to format the variable and the script

//this is my table variable -- I've called it myList
{"colName1", "colName2"}

//this is my script
dt = Current Data Table();
dt << Stack(
	columns(myList),
	Output Table( "New Table" )
);

I have a table with column names colName1, colName2, colName3...

And I would like to be able to stack only certain columns based on a table variable list. I've been able to do this by grouping columns then stacking the whole group, but I've run into situations where I may want to stack a subset of a group of columns, hence this attempt.

The list and script above gives me the error: "Column not found in access or evaluation of bad argument"

I've also tried changing the command to

columns(eval(myList))

but that gives me the same error

Re: Stack column using table variable list

uday_guntupalli — Wed, 06 Feb 2019 14:41:25 GMT

@snapnpop ,
Shouldn't your table variable look like this ?

{"Column1", "Column2"} vs {"Column1, Column2"} ?

Re: Stack column using table variable list

snapnpop — Wed, 06 Feb 2019 14:55:19 GMT

@uday_guntupalli
I've fixed my original post. My table variable was as you typed out.
I had also tried:
("colName1","colName1")
Both with the same errors

Re: Stack column using table variable list

gianpaolo — Wed, 06 Feb 2019 17:30:28 GMT

hello,

you can try with this code

dt = current data table();

// column dialog editor
cd = Column Dialog(
Var = collist( " select columns >>", MinCol( 1 ) ), Hlist( "" ), );
collist= cd["Var"];

//stack operation
dt_stack = dt << Stack(
      columns( collist ), Output Table( "STacked" ),
);

Re: Stack column using table variable list

snapnpop — Wed, 06 Feb 2019 17:22:55 GMT

@gianpalo: the code you've posted allows me to manually select columns to stack each time I run the script.

My goal is to have a table variable with a list of column names to stack, then run a script that utilizes that variable.
The intent is to be able to edit the variable to add/remove columns to be stacked, as the dataset expands/contracts.

Re: Stack column using table variable list

snapnpop — Wed, 06 Feb 2019 21:27:34 GMT

Taking a hint from this thread, I figured out that using the Parse() command works for this.

Table variable myList formatted as such:

{"colName1","colName2"}

and script looks like this:

dt = Current Data Table();
dt << Stack
	( columns( Parse(myList) ), 
	Output Table( "Stacked Data" )
	);