A two dimensional scatterplot

This function is a wrapper around the typical ggplot command to create two dimensional scatterplots, i.e. using geom_point. It provides the option of colouring point by a third variable, one that is usually, though not necessarily categorical. Also, it provides the option of placing the line of best fit on the scatterplot. If points are coloured by a categorical variable, the a different line of best for each value of the categorical variable is provided.

scatterplot(
  x,
  y,
  data,
  by = NULL,
  best_fit_line = FALSE,
  xlab = NULL,
  ylab = NULL
)

Arguments

x

A numeric variable in data. Its values are plotted on the x axis.

y

A numeric variable in data. Its values are plotted on the y axis.

data

A data frame with the x and y variables.

by

An optional variable, usually categorical (factor or character), by which the points in the scatterplot are byed and coloured.

best_fit_line

A logical variable indicating if the line of best fit should shown or not.

xlab

The label of the x-axis (defaults to the x variable name).

ylab

The label of the y-axis (defaults to the y variable name).

Value

A ggplot2::ggplot object, which may be modified with further ggplot2 commands.

Examples

scatterplot(x = attractive, y = trustworthy, data = faithfulfaces)

scatterplot(x = attractive, y = trustworthy, data = faithfulfaces,
            xlab = 'attractiveness', ylab = 'trustworthiness')

scatterplot(x = attractive, y = trustworthy, data = faithfulfaces,
            by = face_sex)

scatterplot(x = trustworthy, y = faithful, data = faithfulfaces,
            by = face_sex, best_fit_line = TRUE)