when do you want to set up new environments in R

Question

per the discussion of R programming styles, I saw someone once said he puts all his custom function into a new environment and attach it. I also remember R environment maybe use

Answer 1

Martin Mächler suggests that this is the one time you might want to consider attach(), although he suggested it in the context of attaching a .Rdata file to the search path but your Q is essentially the same thing.

The advantage is that you don't clutter the global environment with functions, that might get overwritten accidentally etc. Whilst I wouldn't go so far as to call this bad style, you might be better off sticking your custom functions into your own personal R package. Yes, this will incur a bit of overhead of setting up the package structure and providing some documentation to allow the package to be installed, but in the longer term this is a better solution. With tools like roxygen this process is getting easier to boot.

Personally, I haven't found a need for fiddling with environments in 10+ years of using R; well documented scripts that load, process and analyse data, cleaning up after themselves all the while have served me well thus far.

---

Another suggestion for the second part of your question (now deleted) is to use with() (following on from @Joshua's example):

> .myEnv <- new.env()
> .myEnv$a <- 2
> a <- 1
> str(a)
 num 1
> ls.str(.myEnv, a)
a :  num 2
> str(.myEnv$a)
 num 2
> with(.myEnv, a)
[1] 2
> a
[1] 1