27.3 Math symbols in plots

This describes how to use mathematical expressions in plots.

?plotmath

Examples are below. Not all of these display properly here. Not sure why. But hopefully you’ll get the idea.

Note the use of expression() in the examples. For the symbols to appear, expression() must be used like this

Code

dg = mtcars %>% 
  select(wt, mpg, cyl) %>%
  mutate(Cylinders = as.factor(cyl)) %>%
  rename(MPG = mpg)

title = expression(Title~In~Upper~Lower~With~Symbols %=~% tilde(alpha))

g = ggplot(dg, 
           aes(x = wt, 
               y = MPG, 
               color = Cylinders))+
  geom_point(aes(size = MPG))+
  labs(title    = title,
       subtitle = 'Optional Subtitle In Upper Lower',
       caption  = "Optional caption giving more info, Twitter handle, or shameless promotion of pubtheme",
       x = expression(x %+-% y),
       y = 'Vertical Axis Label in Upper Lower')


g %>% 
  pub(xlim = c(0, 6), 
      ylim = c(0, 40))

[1] 40
[1] 80
[1] 20
[1] 140

Code

demo(plotmath)

    demo(plotmath)
    ---- ~~~~~~~~

> #  Copyright (C) 2002-2016 The R Core Team
> 
> require(datasets)

> require(grDevices); require(graphics)

> ## --- "math annotation" in plots :
> 
> ######
> # create tables of mathematical annotation functionality
> ######
> make.table <- function(nr, nc) {
+     savepar <- par(mar=rep(0, 4), pty="s")
+     plot(c(0, nc*2 + 1), c(0, -(nr + 1)),
+          type="n", xlab="", ylab="", axes=FALSE)
+     savepar
+ }

> get.r <- function(i, nr) {
+     i %% nr + 1
+ }

> get.c <- function(i, nr) {
+     i %/% nr + 1
+ }

> draw.title.cell <- function(title, i, nr) {
+     r <- get.r(i, nr)
+     c <- get.c(i, nr)
+     text(2*c - .5, -r, title)
+     rect((2*(c - 1) + .5), -(r - .5), (2*c + .5), -(r + .5))
+ }

> draw.plotmath.cell <- function(expr, i, nr, string = NULL) {
+     r <- get.r(i, nr)
+     c <- get.c(i, nr)
+     if (is.null(string)) {
+         string <- deparse(expr)
+         string <- substr(string, 12, nchar(string) - 1)
+     }
+     text((2*(c - 1) + 1), -r, string, col="grey50")
+     text((2*c), -r, expr, adj=c(.5,.5))
+     rect((2*(c - 1) + .5), -(r - .5), (2*c + .5), -(r + .5), border="grey")
+ }

> nr <- 20

> nc <- 2

> oldpar <- make.table(nr, nc)

> i <- 0

> draw.title.cell("Arithmetic Operators", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x + y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x - y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x * y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x / y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %+-% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %/% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %*% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %.% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(-x), i, nr); i <- i + 1

> draw.plotmath.cell(expression(+x), i, nr); i <- i + 1

> draw.title.cell("Sub/Superscripts", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x[i]), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x^2), i, nr); i <- i + 1

> draw.title.cell("Juxtaposition", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x * y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(paste(x, y, z)), i, nr); i <- i + 1

> draw.title.cell("Radicals", i, nr); i <- i + 1

> draw.plotmath.cell(expression(sqrt(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(sqrt(x, y)), i, nr); i <- i + 1

> draw.title.cell("Lists", i, nr); i <- i + 1

> draw.plotmath.cell(expression(list(x, y, z)), i, nr); i <- i + 1

> draw.title.cell("Relations", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x == y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x != y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x < y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x <= y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x > y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x >= y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %~~% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %=~% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %==% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %prop% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %~% y), i, nr); i <- i + 1

> draw.title.cell("Typeface", i, nr); i <- i + 1

> draw.plotmath.cell(expression(plain(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(italic(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(bold(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(bolditalic(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(underline(x)), i, nr); i <- i + 1

> # Need fewer, wider columns for ellipsis ...
> nr <- 20

> nc <- 2

> make.table(nr, nc)
$mar
[1] 0 0 0 0

$pty
[1] "s"


> i <- 0

> draw.title.cell("Ellipsis", i, nr); i <- i + 1

> draw.plotmath.cell(expression(list(x[1], ..., x[n])), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x[1] + ... + x[n]), i, nr); i <- i + 1

> draw.plotmath.cell(expression(list(x[1], cdots, x[n])), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x[1] + ldots + x[n]), i, nr); i <- i + 1

> draw.title.cell("Set Relations", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %subset% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %subseteq% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %supset% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %supseteq% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %notsubset% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %in% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %notin% y), i, nr); i <- i + 1

> draw.title.cell("Accents", i, nr); i <- i + 1

> draw.plotmath.cell(expression(hat(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(tilde(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(ring(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(bar(xy)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(widehat(xy)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(widetilde(xy)), i, nr); i <- i + 1

> draw.title.cell("Arrows", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %<->% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %->% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %<-% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %up% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %down% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %<=>% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %=>% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %<=% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %dblup% y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x %dbldown% y), i, nr); i <- i + 1

> draw.title.cell("Symbolic Names", i, nr); i <- i + 1

> draw.plotmath.cell(expression(Alpha - Omega), i, nr); i <- i + 1

> draw.plotmath.cell(expression(alpha - omega), i, nr); i <- i + 1

> draw.plotmath.cell(expression(phi1 + sigma1), i, nr); i <- i + 1

> draw.plotmath.cell(expression(Upsilon1), i, nr); i <- i + 1

> draw.plotmath.cell(expression(infinity), i, nr); i <- i + 1

> draw.plotmath.cell(expression(32 * degree), i, nr); i <- i + 1

> draw.plotmath.cell(expression(60 * minute), i, nr); i <- i + 1

> draw.plotmath.cell(expression(30 * second), i, nr); i <- i + 1

> # Need even fewer, wider columns for typeface and style ...
> nr <- 20

> nc <- 1

> make.table(nr, nc)
$mar
[1] 0 0 0 0

$pty
[1] "s"


> i <- 0

> draw.title.cell("Style", i, nr); i <- i + 1

> draw.plotmath.cell(expression(displaystyle(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(textstyle(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(scriptstyle(x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(scriptscriptstyle(x)), i, nr); i <- i + 1

> draw.title.cell("Spacing", i, nr); i <- i + 1

> draw.plotmath.cell(expression(x ~~ y), i, nr); i <- i + 1

> # Need fewer, taller rows for fractions ...
> # cheat a bit to save pages
> par(new = TRUE)

> nr <- 10

> nc <- 1

> make.table(nr, nc)
$mar
[1] 0 0 0 0

$pty
[1] "s"


> i <- 4

> draw.plotmath.cell(expression(x + phantom(0) + y), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x + over(1, phantom(0))), i, nr); i <- i + 1

> draw.title.cell("Fractions", i, nr); i <- i + 1

> draw.plotmath.cell(expression(frac(x, y)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(over(x, y)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(atop(x, y)), i, nr); i <- i + 1

> # Need fewer, taller rows and fewer, wider columns for big operators ...
> nr <- 10

> nc <- 1

> make.table(nr, nc)
$mar
[1] 0 0 0 0

$pty
[1] "s"


> i <- 0

> draw.title.cell("Big Operators", i, nr); i <- i + 1

> draw.plotmath.cell(expression(sum(x[i], i=1, n)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(prod(plain(P)(X == x), x)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(integral(f(x) * dx, a, b)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(union(A[i], i==1, n)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(intersect(A[i], i==1, n)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(lim(f(x), x %->% 0)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(min(g(x), x >= 0)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(inf(S)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(sup(S)), i, nr); i <- i + 1

> nr <- 12

> nc <- 1

> make.table(nr, nc)
$mar
[1] 0 0 0 0

$pty
[1] "s"


> i <- 0

> draw.title.cell("Grouping", i, nr); i <- i + 1

> # Those involving '{ . }' have to be done "by hand"
> draw.plotmath.cell(expression({}(x , y)), i, nr, string="{}(x, y)"); i <- i + 1

> draw.plotmath.cell(expression((x + y)*z), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x^y + z),   i, nr); i <- i + 1

> draw.plotmath.cell(expression(x^(y + z)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(x^{y + z}), i, nr, string="x^{y + z}"); i <- i + 1

> draw.plotmath.cell(expression(group("(", list(a, b), "]")), i, nr); i <- i + 1

> draw.plotmath.cell(expression(bgroup("(", atop(x, y), ")")), i, nr); i <- i + 1

> draw.plotmath.cell(expression(group(lceil, x, rceil)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(group(lfloor, x, rfloor)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(group(langle, list(x, y), rangle)), i, nr); i <- i + 1

> draw.plotmath.cell(expression(group("|", x, "|")), i, nr); i <- i + 1

> par(oldpar)