Facet layer basics
Faceting splits the data up into groups, according to a categorical variable, then plots each group in its own panel. For splitting the data by one or two categorical variables, facet_grid() is best.
Given categorical variables A and B, the code pattern is
plot +
facet_grid(rows = vars(A), cols = vars(B))
This draws a panel for each pairwise combination of the values of A and B.
Here, we'll use the mtcars data set to practice. Although cyl and am are not encoded as factor variables in the data set, ggplot2 will coerce variables to factors when used in facets.
This exercise is part of the course
Intermediate Data Visualization with ggplot2
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
ggplot(mtcars, aes(wt, mpg)) +
geom_point() +
# Facet rows by am
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