There are a couple of different ways to do this.
You can get the values for your Values column into a list using the <<Get Values() message to the column.
You'll need to get rid of the missing values from that list. It's easy to do this by locating the missing rows in the data table with Get Rows Where(). Then the Remove From() function will remove those elements from the list.
Then use For Each() and the Word() function to get rid of the square brackets (i.e., "[]").
dt = Data Table( "Sample.jmp" );
//locate the missing values
missings = dt << get rows where( Is Missing( :values ) );
//get a list of the Values column
lst = :Values << get values;
//Remove the missings from the list
Remove From( lst, As List( missings ) );
//strip the square brackets
For Each( {item, i}, lst, lst[i] = Word( 1, item, "[]" ) );
You could also do all this in the data table by adding a new formula column with the Word() function to strip the square brackets and then getting the values from the new column.
dt=Data Table("Sample.jmp");
new_col = dt << New Column( "New Values", Character,
formula( Word( 1, :Values, "[]" ) )
);
lst = (new_col << get values)[dt <<
get rows where( !Is Missing( :New Values ) )];
The Word() function is my favorite: If you learn only one Formula Editor function, Word() is the one
-Jeff