Creating bar charts
Bar charts are useful for comparing the numbers of elements within subgroups of a population. However, they can be used for other purposes, such as comparing the means of a continuous variable across the levels of a categorical variable. You can create bar charts in ggplot
using geom_bar()
. As an exercise, create a bar chart of numbers of patients by ethnicity by turning the variable ETH
into a factor by using factor()
. The syntax is as follows:
W <- ggplot(T, aes(factor(ETH))) + geom_bar() W
The height of each bar gives the number of patients within each ethnicity. As an exercise, you can create a horizontal bar chart by adding the layer coord_flip()
. The coord_flip()
layer also works for other types of graph, including scatterplots and bar charts.
Now we insert our choice of color and border color using fill
and color
. Let's have an ivory color for the bars, along with dark green borders. The syntax is as follows:
W + geom_bar(fill="ivory", color="darkgreen")...