CODEWITHSUNDEEP
rfunctionsequence
N. Francisco
N. Francisco

Reputation: 3

Calling sequential functions within a function in R

Given a series of functions B1, B2, .., B20

How can you create a function that calls all or some of these predefined functions simultaneously?

What I want for example is a function(start=B1,end=B12) that will call B1 TO B12 functions at the same time.

Upvotes: 0

Views: 459

Answers (2)

Spacedman
Spacedman

Reputation: 94182

You can construct any R object name as a string and then get it. 

> B1 = function(x){x^1}
> B2 = function(x){x^2}
> B3 = function(x){x^3}
> B4 = function(x){x^4}
> getBN = function(N){get(paste0("B",N))}
> getBN(1)
function(x){x^1}
> getBN(2)(2)
[1] 4

If you really want to do this I'd define your function like this:

doBs = function(start=1, end=12, prefix="B"){..stuff happens..}

and that function would be a loop over start:end, construct the function name, evaluate it.

If you really want to call it like doBs(start=B1, end=B2) then you need to get the names of the things passed which you can do with deparse and substitute:

doBs = function(start=B1){first = deparse(substitute(start));first}

> doBs()
[1] "B1"
> doBs(B2)
[1] "B2"
>

and then splitting the string and working out the start/end values to construct all the function names as string from B{start} to B{end} and then getting them and calling them.

Or do the right thing and stick the functions in a list.

Upvotes: 1

sebastian-c
sebastian-c

Reputation: 15395

I would recommend putting all your functions in a list:

B <- list(B1, B2, ..., B20)

That way you can call them with another function:

callB <- function(callnum, ...){
  for(i in callnum){
    B[[i]](...)
  }
}

Upvotes: 1

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