CODEWITHSUNDEEP
arraysrapply
Oscar L
Oscar L

Reputation: 35

How to make apply() pass the object in one of the arguments of the function (not the first)?

I have a some high dimensional arrays and want to apply some functions to them. The problem is I cannot tell apply() (or similar in apply family) that the object to pass the function on is not in the first argument of the function.

Dumb example here:

data <- c(1,2,3,4,5)
myarray <- array(data,dim=c(5,5,2,2),dimnames=list(NULL,
paste("col",1:5,sep=""),
paste("matrix",1:2,sep=""),
paste("slice",1:2,sep="")))

Now, imagine a function with this structure: 

function(arg1,arg2,arg3,data,arg4)

If I want to make apply pass the function to the object "myarray", I need to specify on which argument ("data") is located. I tried this but with no results:

apply(myarray,c(3,4),function,arg1,arg2,arg3,arg4)

Thanks in advance!

Upvotes: 1

Views: 42

Answers (1)

Will
Will

Reputation: 339

If I have understood your right, you need to specify the non iterating arguments. For example:

func <- function(a,b,c){
    return(a*b + c)
}

apply(FUN=func,a=10,b=10,someObject)

The non specified argument is the argument that is iterated over with your specified vector.

Note that if you have a 1D structure

unlist(lapply(FUN=func,a=10,b=10,someObject))

Will likely work better.

Upvotes: 3

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