Using function arguments as column names

Question

I want to create a function that takes the arguments as column names in my dataset.

However when I pass this function with my desired column names as arguments the mutated columns use the literal argument name instead of the passed column names (parameter instead of "cpp").

vehicle <- c("airplane", "bus", "car")
people <- c(300, 40, 5)
cost <- c(50, 5, 2)

small_dataset <- data.frame(vehicle, people, cost)

func <- function(data, parameter) {
  data <- data %>%
    mutate(parameter = cost/people)
  return(data)
}

func(small_dataset, "cpp")

WHAT I WANT:
##    vehicle people cost cpp
## 1 airplane    300   50 0.1666667
## 2      bus     40    5 0.1250000
## 3      car      5    2 0.4000000

WHAT I GET:
##    vehicle people cost parameter
## 1 airplane    300   50 0.1666667
## 2      bus     40    5 0.1250000
## 3      car      5    2 0.4000000

How do I get the function to use the arguments as column names?

Answer 1

Perhaps cleaner here to use base R (instead of dplyr):

func <- function(data, parameter) {
  data[[parameter]] <- with(data, cost/people)
  data
}
func(small_dataset, "cpp")
#    vehicle people cost       cpp
# 1 airplane    300   50 0.1666667
# 2      bus     40    5 0.1250000
# 3      car      5    2 0.4000000