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Add a new component to a ggplot or theme object.

Source: R/plot-construction.r, R/theme.r
gg-add.Rd

This operator allows you to add objects to a ggplot or theme object.

Usage

# S3 method for gganimint
+(e1, e2)

e1 %+% e2

e1 %+replace% e2

Arguments

e1

An object of class ggplot or theme

e2

A component to add to e1

Details

If the first object is an object of class ggplot, you can add the following types of objects, and it will return a modified ggplot object.

  • data.frame: replace current data.frame (must use %+%)

  • uneval: replace current aesthetics

  • layer: add new layer

  • theme: update plot theme

  • scale: replace current scale

  • coord: override current coordinate system

  • facet: override current coordinate faceting

If the first object is an object of class theme, you can add another theme object. This will return a modified theme object.

For theme objects, the + operator and the %+replace% can be used to modify elements in themes.

The + operator updates the elements of e1 that differ from elements specified (not NULL) in e2. Thus this operator can be used to incrementally add or modify attributes of a ggplot theme.

In contrast, the %+replace% operator replaces the entire element; any element of a theme not specified in e2 will not be present in the resulting theme (i.e. NULL). Thus this operator can be used to overwrite an entire theme.

See also

theme

Examples

### Adding objects to a ggplot object
p <- ggplot(mtcars, aes(wt, mpg, colour = disp)) +
  geom_point()

p

p + coord_cartesian(ylim = c(0, 40))

p + scale_colour_continuous(breaks = c(100, 300))

p + guides(colour = "colourbar")


# Use a different data frame
m <- mtcars[1:10, ]
p %+% m


### Adding objects to a theme object
# Compare these results of adding theme objects to other theme objects
add_el <- theme_grey() + theme(text = element_text(family = "Times"))
rep_el <- theme_grey() %+replace% theme(text = element_text(family = "Times"))

add_el$text
#> List of 10
#>  $ family    : chr "Times"
#>  $ face      : chr "plain"
#>  $ colour    : chr "black"
#>  $ size      : num 11
#>  $ hjust     : num 0.5
#>  $ vjust     : num 0.5
#>  $ angle     : num 0
#>  $ lineheight: num 0.9
#>  $ margin    : 'margin' num [1:4] 0points 0points 0points 0points
#>   ..- attr(*, "unit")= int 8
#>  $ debug     : logi FALSE
#>  - attr(*, "class")= chr [1:2] "element_text" "element"
rep_el$text
#> List of 10
#>  $ family    : chr "Times"
#>  $ face      : NULL
#>  $ colour    : NULL
#>  $ size      : NULL
#>  $ hjust     : NULL
#>  $ vjust     : NULL
#>  $ angle     : NULL
#>  $ lineheight: NULL
#>  $ margin    : NULL
#>  $ debug     : NULL
#>  - attr(*, "class")= chr [1:2] "element_text" "element"