Specifies columns to be dropped from the output dataset in a data loop.
drop age, pay, sex;
Commas are optional in variable_list.
Deletes the specified variables from the output dataset. Any variables
referenced must already exist, either as elements of the source data
set, or as the result of a previous
vector, or code statement.
drop() is used, the output dataset will contain all
variables from the source dataset, as well as any defined variables.
The effects of multiple keep and drop statements are cumulative.