Use dplyr inside a function with arbitray column names

function.R

#Use dplyr inside a function with arbitray column names
#The dots stuff is from the internal workings of dplyr
#Don't forget the _ at the end of the group by.
#Other function also have the _ variation with the .dots argument available, 
#but when I first made this in early 2016 not all of them did. 
my_function=function(original_df, variables){
  dots=lapply(variables, as.symbol)
  summarized_data = original_data %>%
    group_by_(.dots = dots ) %>%
    summarize(freq=sum(freq)) %>%
    ungroup() 
}