R Programming Fundamentals

Bar Chart

To make these charts better, we're going to convert the cyl and gear variables in mtcars to factor variables using the following code:

mtcars$cylfactor <- as.factor(mtcars$cyl)mtcars$gearfactor <- as.factor(mtcars$gear)

Use of the factor variables will help the data display properly.

We previously saw how to both automatically change the color of a bar chart (when we made them light blue) and also how to fill a bar chart with another variable. We did this using the following code:

ggplot(mtcars, aes(cyl, fill = gearfactor)) + geom_bar()

The fill indicates the count of each car with a particular type of cylinder and gear. There are a few other ways to display the fill that we can use.

If we want the bars to be next to each other ...