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+ 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:

  • An aes() object replaces the default aesthetics.

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

  • A scale overrides the existing scale.

  • A theme() modifies the current theme.

  • A coord overrides the current coordinate system.

  • A facet specification overrides the 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)) +
base + geom_smooth()
#> `geom_smooth()` using method = 'loess' and formula = 'y ~ x'

# 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' and formula = 'y ~ x'