R Using paste inside of dyplyr functions to build a local function

Question

I am trying to use paste inside of a dplyr's summarize or rename to name a variable when building a local function. I'm getting an Error: unexpected '=' in: " mutate(some.text= x) %>% rename(paste('hp', x, sep= '')="

Here is an example:

data(mtcars)

get.information <- function(df, x) {
  df %>% 
    group_by(hp) %>% 
    summarize(paste('hp', x, sep= "")= n()) %>%
    mutate(some.text= x) 
}

or

get.information <- function(df, x) {
  df %>% 
    group_by(hp) %>% 
    summarize(Frequency= n()) %>%
    mutate(some.text= x) %>%
    rename(paste('hp', x, sep= "")= Frequency)
}

get.information(mtcars, 2)

I'd appreciate any help, thanks in advance!

Answer 1

Try this:

get.information <- function(df, x) {
    var.name = paste0('hp', x)
    var.val = lazyeval::interp('Frequency')
    df %>% 
        group_by(hp) %>% 
        summarize(Frequency= n()) %>%
        mutate(some.text= x) %>%
        mutate_(.dots = setNames(list(var.val), var.name))

}