[R] getOption() versus Sys.getenv

[Sam Albers]

Hi there,

I am trying to distinguish between getOption() and Sys.getenv(). My
understanding is that these are both used to set values for variables.
getOption is set something like this: option("var" = "A"). This can be
placed in an .Rprofile or at the top of script. They are called like this
getOption("var").

Environmental variables are set in the .Renviron file like this: "var" =
"A" and called like this: Sys.getenv("var"). I've seen mention in the httr
package documentation that credentials for APIs should be stored in this
way.

So my question is how does one decide which path is most appropriate? For
example I am working on a package that has to query a database in almost
every function call. I want to provide users an ability to skip having to
specify that path in every function call. So in this case should I
recommend users store the path as an option or as an environmental
variable? If I am storing credentials in an .Renviron file then maybe I
should store the path there as well?

More generally the question is can anyone recommend some good
discussion/documentation on this topic?

Thanks in advance,

Sam

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