vectors, matrices, and lists. Additionally, the operators \code{[[}
and \code{$} may be used to extract a vector from a list. Note that
the default of \code{drop} is not the same than the generic operator:
vectors, matrices, and lists. Additionally, the operators \code{[[}
and \code{$} may be used to extract a vector from a list. Note that
the default of \code{drop} is not the same than the generic operator: