Compute a unique numeric id for each unique row in a data frame.

Source: R/id.r

Properties:

  • order(id) is equivalent to do.call(order, df)

  • rows containing the same data have the same value

  • if drop = FALSE then room for all possibilities

id(.variables, drop = FALSE)

Arguments

.variables

list of variables
drop

drop unused factor levels?

Value

a numeric vector with attribute n, giving total number of possibilities