[R] Question about managing searching path

[Duncan Murdoch]

On 10/17/2006 3:49 AM, Tong Wang wrote:
> Hi all,
>      I'm having sometrouble with managing the seach path, in a function , I need to attach some data set at the begining
> and detach them at the end,  say,     myfunction<- function() { attach(mylist);      .............    detach(mylist) } ,
> the problem is, since I am still debugging this code,  sometimes it got error and ended before reaching the end, thus
> the data is left in the searching path.  
>       What 's the right way to make mylist detached no matter what ?

on.exit, as Vito said.

But you may find that doing the calculations in "with" does a better 
job, i.e.

with(mylist,  [do something])

The advantages of with() are:

  - it takes precedence over local variables; attach (by default) comes 
behind local variables and the global environment.  This may mean your 
code fails when a user happens to have variables with the same name defined.

  - it is a temporary change, so no "detach" is needed.

Duncan Murdoch