ggplot2 中的 reorder() 图问题，带有分组变量

Question

I have a set of data with several values for different regions and different programs, when I try to order my graph from higher to lower accumulated values it works perfectly.

datos = read.csv("https://raw.githubusercontent.com/jaimeyanez/varios/master/datos.csv")

datos %>% 
  group_by(Region) %>% 
  summarise(value= sum(Monto)) %>% 
  ggplot() +
  geom_col(aes(x=reorder(Region,-value), y=value), alpha=.9) +
  labs(title = "Value per group") 

Graph without classification

But if i try to do the same and add a fill aesthetic, it fails

datos %>% 
  group_by(Region, Programa) %>% 
  summarise(value= sum(Monto)) %>% 
  ggplot() +
  geom_col(aes(x=reorder(Region,-value), y=value, fill=Programa), alpha=.9) +
  labs(title = "Value per group") 

Graph with classification

I can change the order manually, but this data is an example and I have to do this whit different grouped variables, so i need to do this in an automatic way.

Thanks,

Answer 1

reorder uses the mean value by default, but your bars show the sum. Change to x = reorder(Region, -value, FUN = sum)