,,,But assigning to the global environment is a bad idea. You're just
asking for trouble -- overwriting without warning something that's
already there.
May I suggest a rule of thumb: When things are difficult or clumsy to
do in R, don't do them.
Of course this is not inviolable, but the OP's request may be one
instance where it applies.
-- Bert
On Fri, Mar 30, 2012 at 7:24 PM, Joshua Wiley <jwiley.ps...@gmail.com> wrote:
> An idiom like this would also work.
>
> f <- function(a,b) list( data.frame(a+rnorm(20), b), loess( a ~ b) )
> lapply(seq_along(out <- f(1:20, 1:20)), function(i) assign(c("c",
> "d")[i], out[[i]], envir = .GlobalEnv))
>
> It is not elegant if you are doing this regularly, but, I think,
> functions typically return lists of output rather than assigning to
> the global environment because presumably one function returns related
> objects so it makes sense for them to stay grouped in a list. If the
> two steps really are unrelated, then use two functions.
>
> It seems like what you want is to have a function return each object
> not in a list but to the global environment, but you would like to be
> able to give them your own names (which makes sense). If this is with
> your own functions, you could adapt them easily to accept names and
> then assign to global.
>
> f <- function(a,b, names = c("a", "b")) {
> assign(names[1], data.frame(a + rnorm(20), b), envir = .GlobalEnv)
> assign(names[2], loess(a ~ b), envir = .GlobalEnv)
> }
> f(1:20, 1:20, c("c", "d"))
>
> I'm not arguing against Gabor's list function, just tossing out a few
> other ideas. I am not familiar with perl, but in R I am used to the
> thing on the left being what is assigned to; the list[a, b] assigning
> to global is counterintuitive to me personally.
>
> Given that this works:
>
> .GlobalEnv[["a"]] <- 1
> a
>
> I was hoping that:
>
> .GlobalEnv[c("c", "d")] <- f(1:20, 1:20)
>
> would also, but alas environments are not subsettable. Interesting question.
>
> Cheers,
>
> Josh
>
> On Fri, Mar 30, 2012 at 6:26 PM, ivo welch <ivo.we...@gmail.com> wrote:
>> thanks, everyone. I should have been clearer (as always). I used the
>> numbers as an example only. I am aware that I can put numbers into
>> vectors and get nice R syntax. my problem is that I usually want to
>> return multiple and/or mixed objects, such as multiple data frames. I
>> should have given as an example something like
>>
>> f <- function(a,b) list( data.frame(a+rnorm(20), b), loess( a ~ b) )
>>
>> weidong---yes, nice syntax, but I don't want to invoke f() twice.
>>
>> peter---I don't think your unlist syntax works. I tried it.
>>
>> gabor---#1-#3 work, but aren't what I really want. #4 is exactly what
>> I wanted. can list[] be added into the standard core R as a feature?
>> it would seem like a natural part of the syntax for functions
>> returning multiple values.
>>
>> justin---mea culpa.
>>
>> regards,
>>
>> /iaw
>> ----
>> Ivo Welch (ivo.we...@gmail.com)
>>
>>
>>
>> On Fri, Mar 30, 2012 at 5:08 PM, Justin Haynes <jto...@gmail.com> wrote:
>>> You can also take a look at
>>>
>>> http://stackoverflow.com/questions/7519790/assign-multiple-new-variables-in-a-single-line-in-r
>>>
>>> which has some additional solutions.
>>>
>>>
>>>
>>> On Fri, Mar 30, 2012 at 4:49 PM, Peter Ehlers <ehl...@ucalgary.ca> wrote:
>>>> On 2012-03-30 15:40, ivo welch wrote:
>>>>>
>>>>> Dear R wizards: is there a clean way to assign to elements in a list?
>>>>> what I would like to do, in pseudo R+perl notation is
>>>>>
>>>>> f<- function(a,b) list(a+b,a-b)
>>>>> (c,d)<- f(1,2)
>>>>>
>>>>> and have c be assigned 1+2 and d be assigned 1-2. right now, I use the
>>>>> clunky
>>>>>
>>>>> x<- f(1,2
>>>>> c<- x[[1]]
>>>>> d<- x[[2]]
>>>>> rm(x)
>>>>>
>>>>> which seems awful. is there a nicer syntax?
>>>>>
>>>>> regards, /iaw
>>>>> ----
>>>>> Ivo Welch (ivo.we...@brown.edu, ivo.we...@gmail.com)
>>>>>
>>>>
>>>> I must be missing something. Why not just assign to a
>>>> vector instead of a list?
>>>>
>>>> f<- function(a,b) c(a+b,a-b)
>>>>
>>>> If it's imperative that f return a list, then you
>>>> could use
>>>>
>>>> (c, d) <- unlist(f(a, b))
>>>>
>>>> to get vector (c, d).
>>>>
>>>> Peter Ehlers
>>>>
>>>>
>>>> ______________________________________________
>>>> R-help@r-project.org mailing list
>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>> PLEASE do read the posting guide
>>>> http://www.R-project.org/posting-guide.html
>>>> and provide commented, minimal, self-contained, reproducible code.
>>
>> ______________________________________________
>> R-help@r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>
>
>
> --
> Joshua Wiley
> Ph.D. Student, Health Psychology
> Programmer Analyst II, Statistical Consulting Group
> University of California, Los Angeles
> https://joshuawiley.com/
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
--
Bert Gunter
Genentech Nonclinical Biostatistics
Internal Contact Info:
Phone: 467-7374
Website:
http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm
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