Quick plots: qplot

Mix.install([
  {:giggly, path: Path.join(__DIR__, "..")},
  {:kino, "~> 0.19"}
  ])

About this notebook

This notebook follows the examples on ggplot2's reference page for qplot(), which covers quickplot() too, in the order the page gives them. Each example shows ggplot2's code first and then Giggly's. An example Giggly cannot draw yet keeps its ggplot2 code and names what it is waiting for, so the page is also a list of what remains.

qplot() makes a plot in one call. Its arguments are the aesthetics, given as expressions, and it guesses a geom from the ones given, or draws the geoms it is told to; it also takes facets, axis limits, log scales and titles. It takes its data from a data frame or from vectors in the calling environment. ggplot2 has deprecated it, to encourage learning ggplot(), with which complex graphics are easier to make. Giggly has no qplot(): a plot is started with Giggly.Plot.new/2 and its layers are added one by one.

A data frame's columns

# Use data from data.frame
qplot(mpg, wt, data = mtcars)
qplot(mpg, wt, data = mtcars, colour = cyl)
qplot(mpg, wt, data = mtcars, size = cyl)
qplot(mpg, wt, data = mtcars, facets = vs ~ am)

Not in Giggly yet: qplot().

Vectors instead of a data frame

set.seed(1)
qplot(1:10, rnorm(10), colour = runif(10))
qplot(1:10, letters[1:10])
mod <- lm(mpg ~ wt, data = mtcars)
qplot(resid(mod), fitted(mod))

Without data, qplot() draws vectors: here a sequence, random numbers, the alphabet, and a model's residuals and fitted values. Not in Giggly yet: qplot() and models fitted by lm(). A Giggly plot draws the columns of a table.

Vectors inside a function

f <- function() {
   a <- 1:10
   b <- a ^ 2
   qplot(a, b)
}
f()

qplot() finds a and b among the function's own variables. Not in Giggly yet: qplot().

Setting an aesthetic

# To set aesthetics, wrap in I()
qplot(mpg, wt, data = mtcars, colour = I("red"))

Not in Giggly yet: qplot().

The geom qplot() guesses

# qplot will attempt to guess what geom you want depending on the input
# both x and y supplied = scatterplot
qplot(mpg, wt, data = mtcars)
# just x supplied = histogram
qplot(mpg, data = mtcars)
# just y supplied = scatterplot, with x = seq_along(y)
qplot(y = mpg, data = mtcars)

Not in Giggly yet: qplot(), and a whole-column function in a mapping, here seq_along(y).

Other geoms

# Use different geoms
qplot(mpg, wt, data = mtcars, geom = "path")
qplot(factor(cyl), wt, data = mtcars, geom = c("boxplot", "jitter"))
qplot(mpg, data = mtcars, geom = "dotplot")

Not in Giggly yet: qplot(), geom_jitter(), and geom_dotplot().