Error: Must request at least one colour from a hue palette

Question

I have some data that looks like this:

<int>   hgnc_symbol
<fctr>  structure
<int>   Promedio_senal
<dbl>   
>8903   MECP2   10225   7.006842    
>3216   CDKL5   10225   7.484454    
>1405   AUTS2   10225   12.801426   
>4254   DAPK1   10225   6.171004    
>12160  RBFOX1  10225   30.756440   
>8903   MECP2   10185   6.595135    
>3216   CDKL5   10185   6.067631    
>1405   AUTS2   10185   11.053545   
>4254   DAPK1   10185   6.222515    
>12160  RBFOX1  10185   25.431652   

Originally it was not a data table, so I turned i tinto one by doing this :

G_OBJ[, structure:=factor(structure, levels = 1:2, labels = c("10225", "10185"))]

setDT(G_OBJ)

I want to do a bar plot where on the x-axis is the name of the gene (hgnc_symbol) and in the y-axis is the gene expresión (Promedio_senal) I have this data on two different brain structure, and I want to show the bars for both structures side by side with different colors. The code I’m using to do this is the following one:

G_OBJ[, structure:=factor(structure, levels = 1:2, labels = c("10225", "10185"))]

ggplot(G_OBJ, aes(hgnc_symbol, Promedio_senal)) + 
  geom_col(aes(fill=structure), position = "dodge")+
  scale_x_discrete("GEN") +
  scale_y_continuous("EXPRESION") +
  labs(title = "GENES_OBJETIVO")

But when I run this the following error message appears:

Error: Must request at least one colour from a hue palette.

I believe that the error is in the part where I try to use structure as the fill color, but I’m not sure; and even if it is that I don’t know what to change to make it correct I appreciate any help

Answer 1

Here is an approach using geom_bar and turning structure as.character (instead of converting it into factor), directly when you define aesthetic parameters.

library(tidyverse)
G_OBJ %>% 
  ggplot(aes(x = hgnc_symbol,
             y = Promedio_senal,
             fill = as.character (structure))) + 
  geom_bar(stat = "identity", position = position_dodge())+
  scale_x_discrete("GEN") +
  scale_y_continuous("EXPRESION") +
  labs(title = "GENES_OBJETIVO") +
  scale_fill_discrete(name = "structure")