ggplot: scale fill manual does not change the colors of the columns

March 27, 2023

I’m tring to color the columns of my plot, but scale_fill_manual comand doesn’t work… Even if I don’t receive any error message, nothing seems to happen

This is my dataset

# A tibble: 14 × 3
   City                      Wage PPA
   <chr>                    <dbl> <dbl>
 1 Livorno                   17.0 107. 
 2 Siena                     17.6 107. 
 3 Terni                     16.7 107. 
 4 Ancona                    17.3 107. 
 5 Roma                      21.4 107. 
 6 Chieti                    23.7  89.3
 7 Teramo                    23.1  89.3
 8 Brindisi                  24.0  89.3
 9 Agrigento                 23.8  89.3
10 Caltanissetta             24.0  89.3
11 Enna                      24.2  89.3
12 Nuoro                     23.0  89.3
13 Oristano                  23.1  89.3
14 Sassari                   23.7  89.3

This is my code

dataset%>%
ggplot(aes(x = reorder(City, Wage), y = Wage)) +
  geom_col() +
  coord_flip()+
  scale_fill_manual(values=c(rep("red",5), rep("blue",9)))+
  theme_classic()

I want to color the columns of the first 5 cities in red and the remaining ones in blue. What Am I setting wrong?

>Solution :

We could create a new variable called Color and assign "red" to the first 5 rows and "blue" to the rest.

For this we have to use fill aesthetics in aes as @Rui Barradas already mentioned in the comments. To set the colors to "red" and "blue" we have to further use scale_fill_manual:

library(ggplot2)
library(dplyr)

df %>% 
  mutate(Color = ifelse(row_number() <= 5, "red", "blue")) %>% 
  ggplot(aes(x = reorder(City, Wage), y = Wage, fill = Color)) +
  geom_col() +
  coord_flip() +
  scale_fill_manual(values = c("red", "blue")) +
  theme_classic()