| plotmath {base} | R Documentation |
If the text argument to one of the text-drawing functions
(text, mtext, axis) in R
is an expression, the argument is interpreted as a mathematical
expression and the output will be formatted according to TeX-like
rules. Expressions can also be used for titles, subtitles and
x- and y-axis labels (but not for axis labels on persp plots).
A mathematical expression must obey the normal rules of syntax for any R expression, but it is interpreted according to very different rules than for normal R expressions.
It is possible to produce many different mathematical symbols, generate sub- or superscripts, produce fractions, etc.
The output from example(plotmath) includes several tables which
show the available features. In these tables, the columns of grey text
show sample R expressions, and the columns of black text show the
resulting output.
The available features are also described in the tables below:
| Syntax | Meaning |
x + y | x plus y |
x - y | x minus y |
x*y | juxtapose x and y |
x/y | x forwardslash y |
x %+-% y | x plus or minus y |
x %/% y | x divided by y |
x %*% y | x times y |
x[i] | x subscript i |
x^2 | x superscript 2 |
paste(x, y, z) | juxtapose x, y, and z |
sqrt(x) | square root of x |
sqrt(x, y) | yth root of x |
x == y | x equals y |
x != y | x is not equal to y |
x < y | x is less than y |
x <= y | x is less than or equal to y |
x > y | x is greater than y |
x >= y | x is greater than or equal to y |
x %~~% y | x is approximately equal to y |
x %=~% y | x and y are congruent |
x %==% y | x is defined as y |
x %prop% y | x is proportional to y |
plain(x) | draw x in normal font |
bold(x) | draw x in bold font |
italic(x) | draw x in italic font |
bolditalic(x) | draw x in bolditalic font |
list(x, y, z) | comma-separated list |
... | ellipsis (height varies) |
cdots | ellipsis (vertically centred) |
ldots | ellipsis (at baseline) |
x %subset% y | x is a proper subset of y |
x %subseteq% y | x is a subset of y |
x %notsubset% y | x is not a subset of y |
x %supset% y | x is a proper superset of y |
x %supseteq% y | x is a superset of y |
x %in% y | x is an element of y |
x %notin% y | x is not an element of y |
hat(x) | x with a circumflex |
tilde(x) | x with a tilde |
ring(x) | x with a ring |
bar(xy) | xy with bar |
widehat(xy) | xy with a wide circumflex |
widetilde(xy) | xy with a wide tilde |
x %<->% y | x double-arrow y |
x %->% y | x right-arrow y |
x %<-% y | x left-arrow y |
x %up% y | x up-arrow y |
x %down% y | x down-arrow y |
x %<=>% y | x is equivalent to y |
x %=>% y | x implies y |
x %<=% y | y implies x |
x %dblup% y | x double-up-arrow y |
x %dbldown% y | x double-down-arrow y |
alpha -- omega | Greek symbols |
Alpha -- Omega | uppercase Greek symbols |
infinity | infinity symbol |
32*degree | 32 degrees |
60*minute | 60 minutes of angle |
30*second | 30 seconds of angle |
displaystyle(x) | draw x in normal size (extra spacing) |
textstyle(x) | draw x in normal size |
scriptstyle(x) | draw x in small size |
scriptscriptstyle(x) | draw x in very small size |
x ~~ y | put extra space between x and y |
x + phantom(0) + y | leave gap for "0", but don't draw it |
x + over(1, phantom(0)) | leave vertical gap for "0" (don't draw) |
frac(x, y) | x over y |
over(x, y) | x over y |
atop(x, y) | x over y (no horizontal bar) |
sum(x[i], i==1, n) | sum x[i] for i equals 1 to n |
prod(plain(P)(X==x), x) | product of P(X=x) for all values of x |
integral(f(x)*dx, a, b) | definite integral of f(x) wrt x |
union(A[i], i==1, n) | union of A[i] for i equals 1 to n |
intersect(A[i], i==1, n) | intersection of A[i] |
lim(f(x), x %->% 0) | limit of f(x) as x tends to 0 |
min(g(x), x > 0) | minimum of g(x) for x greater than 0 |
inf(S) | infimum of S |
sup(S) | supremum of S |
x^y + z | normal operator precedence |
x^(y + z) | visible grouping of operands |
x^{y + z} | invisible grouping of operands |
group("(",list(a, b),"]") | specify left and right delimiters |
bgroup("(",atop(x,y),")") | use scalable delimiters |
group(lceil, x, rceil) | special delimiters |
Murrell, P. and Ihaka, R. (2000) An approach to providing mathematical annotation in plots. Journal of Computational and Graphical Statistics, 9, 582–599.
axis,
mtext,
text,
title
x <- seq(-4, 4, len = 101)
y <- cbind(sin(x), cos(x))
matplot(x, y, type = "l", xaxt = "n",
main = expression(paste(plain(sin) * phi, " and ",
plain(cos) * phi)),
ylab = expression("sin" * phi, "cos" * phi), # only 1st is taken
xlab = expression(paste("Phase Angle ", phi)),
col.main = "blue")
axis(1, at = c(-pi, -pi/2, 0, pi/2, pi),
lab = expression(-pi, -pi/2, 0, pi/2, pi))
## How to combine "math" and numeric variables :
plot(1:10, type="n", xlab="", ylab="", main = "plot math & numbers")
tt <- 1.23 ; mtext(substitute(hat(theta) == that, list(that= tt)))
for(i in 2:9)
text(i,i+1, substitute(list(xi,eta) == group("(",list(x,y),")"),
list(x=i, y=i+1)))
plot(1:10, 1:10)
text(4, 9, expression(hat(beta) == (X^t * X)^{-1} * X^t * y))
text(4, 8.4, "expression(hat(beta) == (X^t * X)^{-1} * X^t * y)",
cex = .8)
text(4, 7, expression(bar(x) == sum(frac(x[i], n), i==1, n)))
text(4, 6.4, "expression(bar(x) == sum(frac(x[i], n), i==1, n))",
cex = .8)
text(8, 5, expression(paste(frac(1, sigma*sqrt(2*pi)), " ",
plain(e)^{frac(-(x-mu)^2, 2*sigma^2)})),
cex= 1.2)
######
# 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="grey")
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), 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("Lists", i, nr); i <- i + 1
draw.plotmath.cell(expression(list(x, y, z)), i, nr); i <- i + 1
# even columns up
i <- 20
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("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.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
# Need fewer, wider columns for ellipsis ...
nr <- 20
nc <- 2
make.table(nr, nc)
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(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)
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)
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)
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
make.table(nr, nc)
i <- 0
draw.title.cell("Grouping", 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); i <- i + 1
# have to do this one by hand
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("|", x, "|")), i, nr); i <- i + 1
par(oldpar)