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Summarise by grouping variable

Source: R/stats.r
stat_summarise.Rd

Applies a function to a specified grouping variable

Usage

stat_summarise(
  mapping = NULL,
  data = NULL,
  geom = "bar",
  position = "identity",
  ...,
  fun = NULL,
  args = list(),
  show.legend = NA,
  inherit.aes = TRUE
)

stat_summarize(
  mapping = NULL,
  data = NULL,
  geom = "bar",
  position = "identity",
  ...,
  fun = NULL,
  args = list(),
  show.legend = NA,
  inherit.aes = TRUE
)

Format

An object of class StatSummarise (inherits from Stat, ggproto, gg) of length 5.

An object of class StatSummarize (inherits from Stat, ggproto, gg) of length 5.

Arguments

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

geom

The geometric object to use to display the data for this layer. When using a stat_*() function to construct a layer, the geom argument can be used to override the default coupling between stats and geoms. The geom argument accepts the following:

  • A Geom ggproto subclass, for example GeomPoint.

  • A string naming the geom. To give the geom as a string, strip the function name of the geom_ prefix. For example, to use geom_point(), give the geom as "point".

  • For more information and other ways to specify the geom, see the layer geom documentation.

position

A position adjustment to use on the data for this layer. This can be used in various ways, including to prevent overplotting and improving the display. The position argument accepts the following:

  • The result of calling a position function, such as position_jitter(). This method allows for passing extra arguments to the position.

  • A string naming the position adjustment. To give the position as a string, strip the function name of the position_ prefix. For example, to use position_jitter(), give the position as "jitter".

  • For more information and other ways to specify the position, see the layer position documentation.

...

additional arguments to pass to layer.

fun

Summarising function to use. If no function provided it will default to length.

args

List of additional arguments passed to the function.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display. To include legend keys for all levels, even when no data exists, use TRUE. If NA, all levels are shown in legend, but unobserved levels are omitted.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. annotation_borders().

Value

A Layer object to be added to a ggplot

Aesthetics

Using stat_summarise requires that you use domain as an aesthetic mapping. This allows you to summarise other data instead of assuming that x is the function's domain.

Examples

library(tidyr)
i <- gather(iris,"key","value",-Species)
ggplot(i, aes(Species, fill = key, domain = value)) +
   geom_bar(aes(y = after_stat(summarise)), stat = "summarise", fun = mean) +
   stat_summarise(aes(y = after_stat(summarise),
                  label = after_stat(summarise)),
                  position = position_stack(vjust = .5), geom = "text", fun = mean)