[R] Help with lapply and tapply

[Michael Hannon]

I think Bert's advice is sound.  Let me add a few, miscellaneous comments:

(1) Some people find "by" easier than "tapply".
(2) The "apply" function can, as I'm sure you (Bert) know, iterate
over a matrix.
(3) Hadley probably has better ways to do all of this (it's hard to keep up).

-- Mike


On Fri, Mar 10, 2017 at 9:22 PM, Bert Gunter <bgunter.4567 at gmail.com> wrote:
> In short, you really need to study the Help files carefully for both,
> as you are using both tapply and lapply incorrectly. If that doesn't
> work, I think you should spend some time with one of the many
> excellent R tutorials on the web. You need to beef up your
> understanding of the syntax.
>
> But briefly:
>
> 1) the tapply call must be of the form tapply(x, fac, fun) where x is
> atomic (i.e. a vector) and fac is a factor that splits x into groups.
> You have obviously got the call all wrong.
>
> 2) And in the second, X must be a list or vector, not a matrix and the
> function needs to have its elements as an argument, something like FUN
> = function(x)FUN1(x, ... your other arguments...)
>
> Cheers,
> Bert
>
>
> Bert Gunter
>
> "The trouble with having an open mind is that people keep coming along
> and sticking things into it."
> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>
>
> On Fri, Mar 10, 2017 at 2:40 PM, Fadhah <fadeh2013 at gmail.com> wrote:
>> Dear all,
>>
>> Thank you in advance for your time and help. I quite new to R and face a problem with lapply and tapply functions.
>> I simulated data and run the simulation 10 times to get 10 different simulated data. I have also built up my function and would like to apply this function to these 10 different data without repeating the code for 10 times. I now that we can use a loop family functions in R such as lapply or tapply functions. I tried both of them but both of them did not work. My data was stored as vector mode list.
>>
>> Here is my data:
>>
>> library(VineCopula)
>> library(copula)
>> Runs= 10 Saveas = vector(mode = "list", length = Runs)
>>  pb <- txtProgressBar(min = 0, max = Runs, style = 3)
>> for(j in 1:Runs){
>>  setTxtProgressBar(pb, j)
>> N=2000
>>  dim=dim
>>  U=runif(N, min=0,max=1)
>>  X = matrix(NA, nrow=N, ncol=2)
>> inds <- U < 0.7
>>  X[inds, ] <- rCopula(sum(inds), claytonCopula(1, dim=2))
>>  X[!inds, ] <- rCopula(N - sum(inds), frankCopula(4, dim=2))
>> Saveas[[j]] = X }
>> Then I built my function. I would like to apply this function to the 10 simulation run. That is I have 10 simulated data and would like to run my function to these data. I tried lapply and tapply function but I got  errors.
>> This is my function:
>>
>> FUN1 <- EM_mixture_copula(data = Saveas[[j]],pi_1=pi_1,pi_2=pi_2,theta = theta,                Theta=Theta, tol = .00001, maxit = 1000)
>> Here is my tries with the errors that I got:
>>
>>> result <- tapply(X,FUN1,simplify = T)
>> Error in tapply(X, FUN, simplify = T) : arguments must have same length.
>>
>>> Result <– lapply(X,FUN1)
>> Error in get(as.character(FUN), mode = "function", envir = envir) : object 'F' of mode 'function' was not found.
>>
>>
>>
>> Once I got the result, I would like to have a summary statistics of my function for each run. So, can I use
>>
>> Summary(result) ?
>>
>> Any help, please?
>> Kinds regards,
>> Fadhah
>>
>> Sent from my iPhone
>>         [[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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 at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.