Rename in dplyr 0.7+ function

Question

I am having difficulty renaming columns in a function using dplyr. I have already found helpful posts on nonstandard evaluation and the use of enquo (e.g., http://dplyr.tidy

Answer 1

To rename multiple columns at once, you have to use !!!:

x <- c("mpg", "cyl")
xnew <- paste(x, 2, sep = ".")
names(x) <- xnew
rename(mtcars, !!!x)

Answer 2

Use := if you want programmatically-assigned names on the LHS of expressions.

x <- "mpg"
xnew <- "mpg2"
rename(mtcars, !!xnew := !!rlang::sym(x))