16.1 Facet wrap
facet_wrap() makes a long ribbon of panels (generated by any number of variables) and wraps it into 2d. This is useful if you have a single variable with many levels and want to arrange the plots in a more space efficient manner.
You can control how the ribbon is wrapped into a grid with
nrow control how many columns and rows (you only need to set one).
as.table controls whether the facets are laid out like a table (
TRUE), with highest values at the bottom-right, or a plot (
FALSE), with the highest values at the top-right.
dir controls the direction of wrap: horizontal or vertical.
ggplot(mpg2, aes(displ, hwy)) + base <- geom_blank() + xlab(NULL) + ylab(NULL) + facet_wrap(~class, ncol = 3) base + facet_wrap(~class, ncol = 3, as.table = FALSE)base
+ facet_wrap(~class, nrow = 3) base + facet_wrap(~class, nrow = 3, dir = "v")base