Function to group by and plot? - R

Question

I'm new to R and I'm doing the R course from DataQuest. I have a csv of forest fires. The file can be downloaded here:

https://archive.ics.uci.edu/ml/machine-learning-databases/forest-fires/

I want to create a function that groups the data by "x" (eg. month or day) and return a bar chart of the count.

library(readr)
library(dplyr)
library(ggplot2)

forestFires <- read_csv("forestfires.csv")

forestFiresCountPlot <- function(x) {
  forestFiresGroup <- forestFires %>%
  group_by(x) %>% 
  summarise(n(x)) %>%
  ggplot(data = forestFiresGroup) + 
    aes(x = x, y = n(x)) +
    geom_bar()
}

forestFiresMonth <- forestFiresCountPlot(month)
forestFiresDay <- forestFiresCountPlot(day)

# Output - Error: Column `x` is unknown

When I call the function, how do I state that month and day are columns?

Answer 1

You can try something like this:

forestFiresCountPlot <- function(x) {

  forestFires %>%  
    group_by_at(x) %>% 
    summarize(n = n()) %>%
    ggplot() + 
      aes_string(x = x, y = “n”) +
      geom_bar(stat = "identity")
}

forestFiresCountPlot("month")
forestFiresCountPlot("day")