[R] Help with lapply and tapply

Bert Gunter bgunter.4567 at gmail.com
Sat Mar 11 06:22:10 CET 2017

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...)


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]]
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