Formula Column from variable list using jsl parse, eval insert, expr and substitute
I use 2 methods to create formula columns depending on whether I know how many variables the formula needsExpr and substitute are easy to read. Section 1 in the code creates several formula columns for each variable in a list for mean(var, byvar)Parse and eval and possibly eval insert create a single formula column that requires a number of variables, the number and name being set by the variable...
