无法在 ggplot 中求和 R shiny

Question

I am working on a R shiny app and I am struggling with ggplot. Here's my dataset:

Year = c(2021, 2022,2023,2021,2023,2020,2021,2023,2022,2023,2022,2021,2020,2020,2023)
Country = c("France", "France", "Italy", "England", "Italy", "England", "Germany", "Germany", "Germany", "France", "France", "Italy", "England", "Italy", "England")
Age = c(22,23,20,24,21,25,21,21,23,24,25,21,20,20,25)
Students = c(1,5,100,43,76,23,43,50,122,5,67,32,53,22,90)
Gender = c("Boy","Girl","Boy","Girl","Boy","Boy","Girl","Girl","Boy","Boy","Girl","Girl","Boy","Girl","Boy") 
df = data.frame(Year, Country, Age, Students, Gender)

In the app, the user can choose to filter by age or to display all ages in a ggplot.

However, ggplot isn't summing Students' values. I don't understand why. How can I tell ggplot to sum values?

Here's my ggplot code:

g <- ggplot(df,
            aes(x=Year, 
                y=Students, 
                fill=Gender))+ 
  geom_bar(stat='identity', position='dodge')+
  geom_text(aes(label = Students))+
  facet_wrap(~ Country) +
  xlab("")
g <- ggplotly(g)
g

Thank you in advance.

Answer 1

While you could use stat_summary or stat="summary" both in geom_bar and geom_text to compute the sum, IMHO the easier option would be to summarise your data outside of ggplot() :

library(ggplot2)
library(plotly)

df <- df |>
  group_by(Country, Year, Gender) |>
  summarise(Students = sum(Students), .groups = "drop")

g <- ggplot(
  df,
  aes(
    x = Year,
    y = Students,
    fill = Gender
  )
) +
  geom_col(position = "dodge") +
  geom_text(aes(label = Students)) +
  facet_wrap(~Country) +
  xlab("")

ggplotly(g)