ggplot2 - opposite colors for fill without recoding

Question

I want to generate a plot and stratify by sex. Unfortunately is my df coded in a way that males are red in the plot and females blue.

df <- data.frame(sex = rbinom(1000, 1, .5),
                 age = rnorm(1000, mean = 50, sd = 10))
df$sex <- as.factor(df$sex)

I can switch the colors with scale_color_manual but the bins have no fill and the outline isn't easy on the eye.

ggplot(df, aes(x = age, color = sex))+
geom_histogram(position = "identity")+
scale_color_manual(values = c("#00BFC4", "#F8766D"))

How to do it properly? Thanks in advance!

Answer 1

If I understand your question correctly you can solve this by mapping sex to fill.

df <- data.frame(sex = rbinom(1000, 1, .5),
             age = rnorm(1000, mean = 50, sd = 10))
df$sex <- as.factor(df$sex)


ggplot(df, aes(x = age, fill = sex))+
geom_histogram(position = "identity")+
scale_fill_manual(values = c("#00BFC4", "#F8766D"))

After that you can switch the colors to match properly

Answer 2

I think you want to specify fill instead of colour in the aes call, and use scale_fill_manual instead of scale_colour_manual. You get a better comparison of the two groups if you use position = "dodge" too:

ggplot(df, aes(x = age, fill = sex)) +
  geom_histogram(position = "dodge", colour = "black") +
  scale_fill_manual(values = c("pink", "blue"))