geom_lollipop {ggalt}

Lollipop charts

Description

The lollipop geom is used to create lollipop charts.

Usage

geom_lollipop(mapping = NULL, data = NULL, ..., horizontal = FALSE,
  point.colour = NULL, point.size = NULL, na.rm = FALSE,
  show.legend = NA, inherit.aes = TRUE)

Arguments

mapping

Set of aesthetic mappings created by aes or 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.

...

other arguments passed on to layer. These are often aesthetics, used to set an aesthetic to a fixed value, like color = "red" or size = 3. They may also be parameters to the paired geom/stat.

horizontal

horizontal is FALSE (the default), the function will draw the lollipops up from the X axis (i.e. it will set xend to x & yend to 0). If TRUE, it wiill set yend to y & xend to 0). Make sure you map the x & y aesthetics accordingly. This parameter helps avoid the need for coord_flip().

point.colour

the colour of the point

point.size

the size of the point

na.rm

If FALSE (the default), removes missing values with a warning. If TRUE silently removes missing values.

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.

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. borders.

Details

Lollipop charts are the creation of Andy Cotgreave going back to 2011. They are a combination of a thin segment, starting at with a dot at the top and are a suitable alternative to or replacement for bar charts.

Use the horizontal parameter to abate the need for coord_flip() (see the Arguments section for details).

A sample of the output from geom_lollipop():

Aesthetics

geom_point understands the following aesthetics (required aesthetics are in bold):

• x

• y

• alpha

• colour

• fill

• group

• shape

• size

• stroke

Examples

df <- data.frame(trt=LETTERS[1:10],
                 value=seq(100, 10, by=-10))

ggplot(df, aes(trt, value)) + geom_lollipop()

ggplot(df, aes(value, trt)) + geom_lollipop(horizontal=TRUE)