CODEWITHSUNDEEP
rfunctionenvironment-variables
Hector Haffenden
Hector Haffenden

Reputation: 1369

Storing variables within a function

How can I store variables locally within a function.

testing <- function(number.info){
  if (!exists('x')){
    x <- 0
  }
    x <- x + number.info
  return(x)
}
testing(2)
testing(2)

As we see here every time I run the function it returns the same value, as x is not being stored.

The motivation behind this is to create a function that can accrue information.

EDIT: Not a repeat question, i did check this answer before hand. The reason is that I don't need it useable outside the function. I just want the function to store it so as i input more data it outputs a 'smarter' result using this new information. I want to do with without using the global environment.

Upvotes: 2

Views: 729

Answers (1)

Onyambu
Onyambu

Reputation: 79188

You can list the value to the global environment. Or the environment you are working from:

testing <- function(number.info){
  if (!exists('x')){
    x <- 0
  }
  x <- x + number.info
  list2env(list(x=x),.GlobalEnv)
  return(x)
}
testing(2)
[1] 2
testing(2)
[1] 4

If you do want to create a new environment then you can do something like:

myenv=new.env()
testing <- function(number.info){

  if (!exists('x',envir = myenv)){
    assign("x", 0,envir = myenv)
  }
  x=get("x",envir = myenv) + number.info
  assign("x", x,envir = myenv)

  return(x)
}
testing(2)
[1] 2
testing(2)
[1] 4

Upvotes: 3

Related Questions