+ is the key to constructing sophisticated ggplot2 graphics. It allows you to start simple, then get more and more complex, checking your work at each step.

# S3 method for gg
+(e1, e2)

e1 %+% e2



An object of class ggplot or a theme.


A plot component, as described below.

What can you add?

You can add any of the following types of objects:

  • A aes() objects replaces the default aesthetics.

  • A layer created by a geom_ or stat_ function adds new layer.

  • A scale overrides the existing scale.

  • A theme modifies the current theme.

  • A coord overrides current coordinate system.

  • A facet specificatio override current faceting.

To replace the current default data frame, you must use %+%, due to S3 method precedence issues.

You can also supply a list, in which case each element of the list will be added in turn.

See also



base <- ggplot(mpg, aes(displ, hwy)) + geom_point() base + geom_smooth()
#> `geom_smooth()` using method = 'loess'
# To override the data, you must use %+% base %+% subset(mpg, fl == "p")
# Alternatively, you can add multiple components with a list. # This can be useful to return from a function. base + list(subset(mpg, fl == "p"), geom_smooth())
#> `geom_smooth()` using method = 'loess'