Yes. To elaborate a bit on Ista's reply:
A) The only way I can imagine hiding info from a user would be to encrypt it. This could be done programmatically I think, but I would have to research it to figure out how. B) If all you want to do is prevent the info from being printed, just create e.g an S3 class of type "foo" that inherits from "data.frame" with your info as an attribute and provide a print.foo method that just prints the data frame without the attribute. Your function can access and use the attribute any way it likes. Cheers, Bert Bert On Feb 20, 2017 1:27 PM, "Ista Zahn" <istaz...@gmail.com> wrote: It depends on what you mean by 1). If you mean "won't annoy the user" then yes, e.g., add something to the class attribute. If 1) means "can't be discovered by the user" then no (at least not easily). Anything you can see they can see. Best, Ista On Feb 20, 2017 4:21 PM, "stephen sefick" <ssef...@gmail.com> wrote: Hello, I would like to add something to a data frame that is 1) invisible to the user, 2) has no side effects, and 3) I can test for in a following function. Is this possible? I am exploring classes and attributes and I have thought about using a list (but 1 and 2 not satisfied). Any help would be greatly appreciated. I did not provide a reproducible example because I see this as more of a R language question, but I will be happy to make a toy example if that would help. I appreciate all of the help. kindest regards, -- Let's not spend our time and resources thinking about things that are so little or so large that all they really do for us is puff us up and make us feel like gods. We are mammals, and have not exhausted the annoying little problems of being mammals. -K. Mullis "A big computer, a complex algorithm and a long time does not equal science." -Robert Gentleman [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.