Graphics Reference
In-Depth Information
Solution
Use
geom_bar()
and map a variable
fill
. This will put
Date
on the x-axis and use
Cultivar
for the fill color, as shown in
Figure 3-16
:
library(gcookbook)
# For the data set
ggplot(cabbage_exp, aes(x
=
Date, y
=
Weight, fill
=
Cultivar))
+
geom_bar(stat
=
"identity"
)
Figure 3-16. Stacked bar graph
Discussion
To understand how the graph is made, it's useful to see how the data is structured. There are
three levels of
Date
and two levels of
Cultivar
, and for each combination there is a value for
Weight
: