Re: [R] Problem accessing .Rdata objects in a loop

[francy]

Thank you both for your answers. Sorry if I haven't explained myself
well, Michael, that is what I was looking for. Using get(n) works,
thank you. I wish I could have used saveRDS and readRDS, but it was
not my saved object… In any case thanks again.

2012/4/17 Michael Weylandt [via R] <ml-node+s789695n4565280...@n4.nabble.com>:
> I'm not sure that's francy's problem. This seems to work for me:
>
> # Some fake data
> nms <- letters[1:5]
> lapply(nms, function(x) assign(x, rnorm(10), .GlobalEnv))
>
> # Make some .Rdata files
> lapply(nms, function(x) save(list =x, file = paste0(x, ".Rdata")))
>
> # Check they are there
> list.files()
>
> # Bring them in and do operations
> for(nm in nms){
>     load(paste0(nm,".Rdata"))
>    print(max(get(nm))) # Works
> }
>
> Francy's problem seems to be trying to use `n` (the symbol, not the
> character vector) to access the loaded objects instead of get. Use of
> the backticks doesn't do what I think you (Francy) think it does here.
>
> Of course, I think this is all a little easier if one uses saveRDS /
> readRDS which can assign directly to an object upon load (xxx <-
> loadRDS(filename)) -- Duncan Murdoch pointed these out to me just a
> few weeks ago.
>
> Michael
>
> On Tue, Apr 17, 2012 at 12:07 PM, Bert Gunter <[hidden email]> wrote:
>
>> Try reading ?load again.
>> It takes a single filename only.
>>
>> Also 'n' is a character, not a symbol for a variable.  I think you
>> need to do some reading on basic programming. Try An Introduction to R
>> (part of the distro) to get you going.
>>
>> -- Bert
>>
>> On Tue, Apr 17, 2012 at 8:38 AM, francy <[hidden email]> wrote:
>>> Hi,
>>>
>>> I am trying to access many .Rdata objects and do some operations with
>>> them
>>> using a loop. I can load the files but can't access them. The files'
>>> names
>>> are stored in a character vector called "names".  After loading the
>>> objects,
>>> I can view each one using ls() and see that two objects are present for
>>> each. I am trying to access the one with the name which is the same as
>>> the
>>> name of the .Rdata. I can access individual .Rdata object using backticks
>>> around its name like this:
>>>
>>> names<- c("df1", "df2", "df3")
>>> load(paste(path, "/", df1, ".RData", sep="")
>>> df<- `df1`
>>>
>>> But when I try using the variable name in a loop it does not work:
>>>
>>> for (n in names) {
>>> print(names)
>>> load(paste(path,  "/", names, ".RData", sep=""))
>>> df<- `n`
>>> ###do some other operations with each object
>>> }
>>>
>>> Could you please help me understand what I can do to view these objects?
>>>
>>> Thank you.
>>>
>>> --
>>> View this message in context:
>>> http://r.789695.n4.nabble.com/Problem-accessing-Rdata-objects-in-a-loop-tp4565154p4565154.html
>>> Sent from the R help mailing list archive at Nabble.com.
>>>
>>> ______________________________________________
>>> [hidden email] 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
>>
>> ______________________________________________
>> [hidden email] 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.
>
> ______________________________________________
> [hidden email] 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.
>
>
> ________________________________
> If you reply to this email, your message will be added to the discussion
> below:
> http://r.789695.n4.nabble.com/Problem-accessing-Rdata-objects-in-a-loop-tp4565154p4565280.html
> To unsubscribe from Problem accessing .Rdata objects in a loop, click here.
> NAML


--
View this message in context: 
http://r.789695.n4.nabble.com/Problem-accessing-Rdata-objects-in-a-loop-tp4565154p4567321.html
Sent from the R help mailing list archive at Nabble.com.
        [[alternative HTML version deleted]]


______________________________________________
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.