What is a good way to create a matrix of index variables based on all
possible combinations of a list of factors in a data-frame, say list(age, sex)? age
and sex are numeric and factor variables in a dataframe, with 99 and 2
values, respectively.
I would like to use these for subsetting the
[EMAIL PROTECTED] wrote:
What is a good way to create a matrix of index variables based on all
possible combinations of a list of factors in a data-frame, say list(age, sex)? age
and sex are numeric and factor variables in a dataframe, with 99 and 2
values, respectively.
I would like to use
