Ytukyg

So I have a large list of objects (200+) which only contain a numeric value. I want to apply the same mathematical (get the 80% of the value) function for all of them, but it's not working out for me.

Here's a small example.

a = 680



b = 820



c = 1040



list = as.list(ls())



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

And I get an error saying non-numeric argument to binary operator. I get that this might be happening because the software is applying the function to the names in the list and no the numerical values, but for the life of me I can't make it work and haven't been able to find this exact issue online. I know the answer must be so simple but I'm a newbie, really. Any help is appreciated.

Thank you!!

You are looking for the mget function: This is a multivariate format of get

thus:

a = 680



b = 820



c = 1040



list = mget(ls())## This is the part you need to change



fun = function(x){x*.8}



for (i in list){

  fun(i)

}

You get an error because ls() only returns the names of the variables you've defined. ("a", "b" and "c")

Having said that, this example could be more easily be done using regular vector and scalar multiplication.

x = c(680, 820, 1040)

x * .8

If for some reason you want you use a list and function anyway I would recommend using lapply, like so:

a = 680

b = 820

c = 1040



list = list(a, b, c)



fun = function(x){ x*.8 }



lapply(list, fun)

Use eapply to apply a function to all variables in an environment. However, I recommend you to first build a list of numeric variables and use lapply(myList, fun) as variables in an environment can easily be manipulated unintentionally. Refer to the code below:

##### Solution 1 using eapply() #####

# Build a new temporary environment to save all numeric variables

tempEnv <- new.env()

tempEnv$a = 680

tempEnv$b = 820

tempEnv$c = 1040



fun = function(x){x*.8}



# apply fun() to all variables in "tempEnv"

eapply(tempEnv, fun)





##### Solution 2 using lapply() (Recommended) #####

# Define all variables in a list

myList <- list(a = 680, 

               b = 820, 

               c = 1040)



# apply fun() to all values in myList

lapply(myList, fun)