how to use the value of a variable as the name of another variable

Question

In R , how to use the value of a variable as the name of another variable

for example:

SCE<-function(i){ #x<-paste0("SCE",i) x<-c(i,i+1) return (x) } x<-paste0("SCE",1) y<-SCE(1) paste0("SCE",1)=SCE(1) cat("SCE",1)=SCE(1)

How can I make the value of variable x (string) as the name of another variable y (unknown data type)? Here, the final result I want to get is a variable named SCE1, its type is numeric, and its value is 1 2

The problem I actually encountered is: I have a repetitive code that I want to use a for loop to complete, but every time I complete it, I want to save the result as a variable so that I can use it later.

SCE<-function(i){ #x<-paste0("SCE",i) x<-c(i,i+1) return (x) } for (i in 2:9) { x<-paste0("SCE",i) y<-SCE(i) }

Every time the for loop is completed, I hope to get a variable of SCE+number, whose value is the result of the corresponding SCE function

Thank you very much!

Waldi · Accepted Answer · 2021-04-01 16:17:49Z

if I understand your question correctly, assign could be an option :

SCE<-function(i){ assign(x = paste0("SCE",i), value = c(i,i+1), envir = parent.frame()) } SCE(1) SCE1 #> [1] 1 2

akrun · Accepted Answer · 2021-04-01 16:21:35Z

The value of

paste0("SCE", 1) #[1] "SCE1"

We may need the brackets as well

x <-paste0("SCE(", 1, ")")

and then do an eval(parse

eval(parse(text = x)) #[1] 1 2

which is same as executing the function

y <- SCE(1) y #[1] 1 2

If the OP wanted to get the values from "SCE1", then extract the function part and the input argument separately

match.fun(sub("\\d+", "", x))(as.numeric(sub("\\D+", "", x))) #[1] 1 2

If we want to create objects in the global environment (not recommended), an option is list2env, though it is better to store it in a named list

lst1 <- setNames(lapply(1:5, SCE), paste0("SCE", 1:5)) list2env(lst1, .GlobalEnv)

First of all, thank you very much for your quick answer, but in fact I didn't seem to state my question clearly. The problem I actually encountered is: I have a repetitive code that I want to use a for loop to complete, but every time I complete it, I want to save the result as a variable so that I can use it later.
@Alen Have you checked the solution at the end with match.fun
@Alen Do you want to create object names SCE1, SCE2 etc with the input 1, 2, ..
If you use for examplelapply, you can loop over a block of code that returns the last statement to you in a list when done. Could you work with that? Creating dynamic variable names is seldom the right answer and a good indication that something can be done better in another way

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