How to create a loop and add column in subset tables and add value based on specific column value?

[#1]

Hi all, I have a table subset

I have two questions.

1. How can create a loop that adds column "Ref" to every subset table? 

2. Also, is it possible that the value of the created column will be based on the highest number of N Rows with a specific value?

For example, the new column to be added will be Ref. Column Ref's value will be based on Column Country, wherein it should add 1 to the highest N Rows Value of America only.

Country	N Rows	Ref
Argentina	4
America	0
America	5	1
Brazil	2
Brazil	4
Canada	2

TIA

[#2]

I am not sure what your definition of as "column subset" is.  Is what you are referring to, the data tables created from

     Tables=>Subset

when  Subset By is checked

and a separate table for each level of the variable(s) selected is made?

[#3]

After I have subset the table, how can I create a loop to add a column "Ref" on all the subsetted tables? 

*Will rephrase the question

[#4 · Accepted solution]

Here is an example of one way to do the looping.  The real issue is how to get the list of tables to loop across.  This example assumes that 

     Tables=>Subset

with a Subset By was used

names default to here(1);
dt =
// Open Data Table: Big Class.jmp
// → Data Table( "Big Class" )
Open( "$SAMPLE_DATA/Big Class.jmp" );

dtSubsetList = dt << Subset(
	By( :sex ),
	All rows,
	Selected columns only( 0 ),
	columns( :name, :age, :height, :weight )
);

for each( {table}, dtSubsetList,
	table << new column( "Ref");
	wait(0);
	table:ref[table << get rows where( :age == col max(:age))]=1;
);

[#5]

What if my data looks like this? The column Country is in character type, how can I get its highest N Rows? Assuming that I am getting the highest N Rows from America. From the example you have given, I think it is in numeric data type

Country	N Rows	Ref
Argentina	4
America	0
America	5	1
Brazil	2
Brazil	4
Canada	2

[#6]

I assume something similar to this will be what you need

table:ref[table << get rows where( :Country == "America" & :N Rows == col max(:N Rows, :Country))]=1;

I suggest you take the time to read the Scripting Guide, to learn JSL.  If you are not familiar with programming and at least one programming language, I suggest you search the internet for a free course on "Learn how to Program".