Create a dual axis column bar chart using ggplot in R

Question

Hi, i need to create a dual axis bar chart and also column chart using 1 variable and a categarical column. Can someone help using ggplot?

Like below charts (only bars)

  

Answer 1

Add position = "stack" in geom_bar() function to stack bar over each other.

See the below example.

> ggplot(mpg, aes(displ, hwy, fill = factor(cyl))) + geom_bar(stat = "identity",position = "stack")