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Exercise

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.

Instructions 1/3
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  • 1
    • Facet the plot in a grid, with each am value in its own row.
    • 2
      • Facet the plot in a grid, with each cyl value in its own column.
    • 3
      • Facet the plot in a grid, with each am value in its own row and each cyl value in its own column.