CODEWITHSUNDEEP
rconcatenation
cthulhukk
cthulhukk

Reputation: 99

Calling variables from concatenated strings

I have three variables which I want to call from a vector containing variable names produced by concatenating the string "variable." with the suffix "ONE", "TWO" and "THREE", as per code below:

variable.ONE <- 1
variable.TWO <- 2
variable.THREE <- 3
j <- c("ONE","TWO","THREE")
variables <- paste0("variable.",j)

"Variables" prints:

variables
[1] "variable.ONE"   "variable.TWO"   "variable.THREE"

I am looking for a way to return the values of all three variables contained in the vector "variables", hence:

[1] 1 2 3

However, calling the variables contained in "variables" does not work as intended:

get(variables) produces:

[1] 1

eval(noquote(variables))) produces:

[1] variable.ONE   variable.TWO   variable.THREE

eval(as.name(variables))) produces:

[1] 1

These attempts are only three of many, none of which brought me to the desired - and simple - output of:

[1] 1 2 3

Therefore, I would greatly appreciate any help you may be able to offer!

Thanks in advance!

Upvotes: 4

Views: 74

Answers (1)

VFreguglia
VFreguglia

Reputation: 2311

You can use mget(variables) for a character vector, returning a list of objects.

Note that there is no way to ensure that each element of variables refers to an atomic object of the same type (e.g., what if variable.TWO <- "b"?), so it is expected that the result should be a list instead of a vector.

You can achieve your desired output with unlist(mget(variables)).

Upvotes: 4

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