R is not lazy. It has non-standard evaluation mechanisms (formulas, promises, quosures...) that enable to you to write domain-specific languages that "do what the user meant".
If your code (or the code of the libraries you're using) doesn't use any non-standard evaluation tools, evaluation will be eager and work like any other ALGOL language.
It is possible to make some objects behave in a lazy way, but this is also true of many other languages.
If your code (or the code of the libraries you're using) doesn't use any non-standard evaluation tools, evaluation will be eager and work like any other ALGOL language.
It is possible to make some objects behave in a lazy way, but this is also true of many other languages.