Temporarily change system environment variables.

with_envvar(new, code, action = "replace")

local_envvar(new, action = "replace", .local_envir = parent.frame())

## Arguments

new [named character] New environment variables [any] Code to execute in the temporary environment should new values "replace", "prefix" or "suffix" existing variables with the same name. [environment] The environment to use for scoping.

## Value

[any]
The results of the evaluation of the code argument.

## Details

if NA is used those environment variables will be unset. If there are any duplicated variable names only the last one is used.

withr for examples
Sys.setenv()