na.value 不能在 r 中的 scale_fill_continuous() 中工作

Question

I want to set the color of NA value.

But it does not work when I set scale_fill_continuous(na.value = 'red') .

Reproducible example like this:

df = data.frame(
  grade = c('class 1', 'class 1', 'class 2'),
  sex   = c('Female', 'Male', 'Female'),
  n     = c(1,5,3))
df

df %>% ggplot(aes(x = sex, y = grade, fill = n)) +
  geom_tile()

df %>% ggplot(aes(x = sex, y = grade, fill = n)) +
  geom_tile() +
  scale_fill_continuous(na.value = 'red')

Any help will be highly appreciated!

Answer 1

There is no NA value in the data, you need to first generate it and then use the plotting code.

One way to generate the missing combination is to use tidyr::complete .

library(ggplot2)

tidyr::complete(df, grade, sex) %>%
  ggplot(aes(x = sex, y = grade, fill = n)) +
  geom_tile() + 
  scale_fill_continuous(na.value = 'red')