Hi, I know that racket has an ‘object’ for representing non-existent values (other than #f or (void), more something like ‘nothing’) in some lib. Unfortunately, I can’t remember where I found it in the docs! Does anybody know the name or where I can find it?

Maybe undefined

But it’s meant for representing that a variable is not yet initialized.

that’s it! Thanks!

Hmm. Ok, so not really what I’m looking for

Essentially, I was hoping to have something similar to NA in R, such that I could still have #f and #t to make boolean vectors with missing values

I would simply use (struct NA ()) and then only create one instance.

If you need it, there are some struct properties that can be used to change the way the value is printed.

I had not thought about that, but it seems like a great idea. Thanks again!