r: Can't use get() to retrieve variable name in colnames()

Asked Aug 07 '20 at 19:48

Active Aug 10 '20 at 15:23

Viewed 22 times

I'm trying to write a code snippet that will allow others to copy and paste it with minimal changes. There is a variable name that will be different every time, so I would like the other users to be able to assign the variable name to a variable at the head and then I will reference that variable using get() or assign(). This variable will be a data frame. For instance:

name_of_frame <- "number_one"
# This is where they will name the variable

assign (name_of_frame, read.csv("....", header=FALSE))

new_variable <- get(name_of_frame) [2:nrow(get(name_of_frame)),]

These work fine. The one that doesn't is this:

colnames(get(name_of_frame)) <- new_vector

This throws the error: Error in colnames(get(name_of_frame)) <- new_vector : could not find function "get<-"

If I substitute this it works fine:

colnames(number_one) <- new_vector

Why is this the only context where I can't use get(name of variable) to substitute for the variable?

edited Aug 10 '20 at 15:23

asked Aug 07 '20 at 19:48

leviemb

why's `<=` in 1st line? – Amandeep Jiddewar Aug 07 '20 at 19:54
1

If you replace the `<=` with ` – Moritz Schwarz Aug 07 '20 at 19:55
Generally using [get/assign is not advisable](https://stackoverflow.com/questions/17559390/why-is-using-assign-bad). Often there are more R-like ways to do things. You cannot use special functions like `colnames – MrFlick Aug 07 '20 at 20:10
Sorry, I had to retype my code, but the original has – leviemb Aug 10 '20 at 15:26
It looks like this has been closed, I will try to re-ask in a clearer way. – leviemb Aug 10 '20 at 16:04

r: Can't use get() to retrieve variable name in colnames()

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