last(x,...)xts::last is deployed.data.table::last. Any arguments here are passed through to xts::last.data.frame or data.table. Otherwise, whatever xts::last returns (if package xts has been loaded, otherwise a helpful error).
If any argument is supplied in addition to x (such as n or keep in xts::last), regardless of x's type, then xts::last is called if xts has been loaded, otherwise a helpful error.NROW, head, tail