dplyr
dplyr with bang bang example
Varying the name of the output variable
We need to do the following:
- Use quo_name() to convert the input expression to string
- Use := helper provided by rlang
# https://www.onceupondata.com/2017/08/12/my-first-steps-into-the-world-of-tidyeval/
add_tag_count <- function(x, cname, count_col){
cname <- enquo(cname)
count_col <- enquo(count_col)
count_col_name <- quo_name(count_col)
x %>%
mutate(!!count_col_name := map_int(!!cname, length))
}Capturing multiple variables
freq_tbl <- function(df, ..., percent = TRUE){
group <- quos(...)
out <- df %>%
group_by(!!!group) %>%
summarise(freq = n()) %>%
arrange(desc(freq)) %>%
ungroup()
if(percent == TRUE){
out <- out %>%
mutate(percentage = 100*freq/sum(freq))
}
return(out)
}