3  LaTeX in Base Plot

I want to display LaTeX equations as the names on one of the axis, using basic plot. I will do this using the TeX() function from {latex2exp}.

Let us generate some dummy data:

library(dplyr)

Attaching package: 'dplyr'

The following objects are masked from 'package:stats':

    filter, lag

The following objects are masked from 'package:base':

    intersect, setdiff, setequal, union

n <- 100
tb <- tibble(
  class = rep(
    c("Model 1 with $X \\sim N(0,1)$",
      "Model 2 with $X \\sim N(1,1)$"),
    each = n
  ),
  y = c(
    rnorm(n = n, mean = 0, sd = 1),
    rnorm(n = n, mean = 1, sd = 1)
  )
) |> 
  mutate(
    class = factor(class)
  )
tb

# A tibble: 200 × 2
   class                                y
   <fct>                            <dbl>
 1 "Model 1 with $X \\sim N(0,1)$"  1.06 
 2 "Model 1 with $X \\sim N(0,1)$"  1.51 
 3 "Model 1 with $X \\sim N(0,1)$" -0.442
 4 "Model 1 with $X \\sim N(0,1)$" -0.427
 5 "Model 1 with $X \\sim N(0,1)$" -1.00 
 6 "Model 1 with $X \\sim N(0,1)$" -0.194
 7 "Model 1 with $X \\sim N(0,1)$"  0.619
 8 "Model 1 with $X \\sim N(0,1)$" -0.751
 9 "Model 1 with $X \\sim N(0,1)$"  2.20 
10 "Model 1 with $X \\sim N(0,1)$"  0.176
# ℹ 190 more rows

The levels:

lvls <- levels(tb$class)
lvls

[1] "Model 1 with $X \\sim N(0,1)$" "Model 2 with $X \\sim N(1,1)$"

par(mar = c(2.1, 10.1, 2.1, 2.1))
boxplot(
  y ~ class,
  data = tb,
  horizontal = TRUE,
  las = 1,
  xlab = NULL, ylab = NULL,
  yaxt = "n"
)


# Setting the y axis (with the LaTeX expressions)
axis(
  2, 
  at = 1:length(lvls), 
  labels = c(latex2exp::TeX(lvls)),
  las = 2
)

Note

Unfortunately, the \mathcal{} is not supported by R.

Now, what if we want to add a new line to the labels? It becomes a bit ugly…

tb <- tibble(
  class = rep(
    c(
      "$\\overset{\\normalsize{Model~1~with}}{X \\sim N(0,1)}$",
      "$\\overset{\\normalsize{Model~2~with}}{X \\sim N(1,1)}$"
    ),
    each = n
  ),
  y = c(
    rnorm(n = n, mean = 0, sd = 1),
    rnorm(n = n, mean = 1, sd = 1)
  )
) |> 
  mutate(
    class = factor(class)
  )
lvls <- levels(tb$class)

par(mar = c(2.1, 7.1, 2.1, 2.1))
boxplot(
  y ~ class,
  data = tb,
  horizontal = TRUE,
  las = 1,
  xlab = NULL, ylab = NULL,
  yaxt = "n"
)
# Setting the y axis (with the LaTeX expressions)
axis(
  2, 
  at = 1:length(lvls), 
  labels = c(latex2exp::TeX(lvls)),
  las = 2
)