Creating a column with concatenated values

[#1]

Hey all, 
I'm trying to create new column which will include to rows/values. The first one is a variable and the second one is a concatenated expression of two variables.

No matter what I tried, I get an empty cell in the concatenated value. Can you please advise?

Example of what I tried:

stiop=10; stiPLL=20; stiPHL=30;
STIarg={char(stiop),char(stiPLL) ||"<PL<"|| char(stiPHL)};

Operations<<
New Column( "STI", "nominal", Set Values( STIarg ) );

[#2]

I am confused.  Can you please provide an example of what you expect your new column will look like?

[#3]

Sorry for the confusion.
The new column suppose to look like that:

STI

10

20<PL<30

[#4]

The action of JMP is to loop one row at a time through the data table when running a Formula() or Set Each Value().And by default, it will only be outputting to the current row.  There are different ways to solve your issue, but this is the way I would do it

Names Default To Here( 1 );
Operations = Open( "$SAMPLE_DATA/Big Class.jmp" );

stiop = 10;
stiPLL = 20;
stiPHL = 30;
STIarg = {Char( stiop ), Char( stiPLL ) || "<PL<" || Char( stiPHL )};

Operations << New Column( "STI",
	character,
	Set each Value(
		If( Mod( Row(), 2 ) != 0,
			:STI = Eval( STIarg[1] ),
			:STI = Eval( STIarg[2] )
		)
	)
);

or if you want it to only have the 2 rows

Names Default To Here( 1 );
Operations = Open( "$SAMPLE_DATA/Big Class.jmp" );

stiop = 10;
stiPLL = 20;
stiPHL = 30;
STIarg = {};
Insert into(STIarg, char(stiop));
Insert into(STIarg,Char( stiPLL ) || "<PL<" || Char( stiPHL ) );

Operations << New Column( "STI",
	character, set values(STIarg));

[#5]

As an alternative, you could use EvalList to evaluate the list entries before they get used via Set Values..

Please also note that you have to specify the data type: Character.

For numeric columns, even for ones with modeling type: Nominal the value will be casted -> Numeric:

"10" will survive as 10, but the second value will get lost.

stiop=10; stiPLL=20; stiPHL=30;
STIarg=EvalList({char(stiop),char(stiPLL) ||"<PL<"|| char(stiPHL)});

New Column( "STI",Character, Set Values( STIarg ) );