The infamous P-I-E
Intuitively, you can think about a pie chart as a stacked bar chart that has been 'wrapped' around some central axis. Conveniently, this intuition fits very well with how they are made in ggplot2.
Supplied is code to summarize our who_disease data into a data frame containing three diseases: measles, mumps, and,other, along with their total number of cases in the data.
Your job is to turn the empty ggplot object into a stacked bar-chart, then into a pie-chart by using the transform coord_polar(theta = 'y').
Notice how I have set x = 1 in the aesthetics. This is because we only want one bar chart here. We'll learn about multiple stacked bar charts in the next lesson!
Cet exercice fait partie du cours
Visualization Best Practices in R
Instructions
- Add a column geometry (
geom_col()) to the supplied ggplot object. - Switch to polar coordinates by adding
coord_polar().
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
# Wrangle data into form we want.
disease_counts <- who_disease %>%
mutate(disease = ifelse(disease %in% c('measles', 'mumps'), disease, 'other')) %>%
group_by(disease) %>%
summarise(total_cases = sum(cases))
ggplot(disease_counts, aes(x = 1, y = total_cases, fill = disease)) +
# Use a column geometry.
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# Change coordinate system to polar and set theta to 'y'.
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