how to show $\{ X_t \}$ in the title of a plot of R

Question

How to show $\{ X_t \}$ of Latex in the title of a plot of R?

For example

 plot(slot(x,"GRID"),slot(x,"PATH"),type="l", xlab="Time t",ylab="X",
 main=paste("Simulation of \{X_t\}"))

Thanks!

Answer 1

Assuming you will provide meaningful arguments for the slot expressions, then I think there is a reasonable chance that this is what you want:

plot(1:10,1:10,type="l", xlab="Time t",ylab="X",
      main=expression("Simulation of {"*X[t]*"}"))

This is a plotmath expression that presents "t" as a subscript of "X" and that expression is enclosed in curley braces. If I have misread your request, then note that the "*" character is a separator in the plotmath syntax and the braces are simply characters than can be deleted. (The LaTeX expressions don't make a lot of sense to those of us who just use the plotmath syntax, so describing what you want in prose or mathematical jargon would work better for any clarifications.)

Answer 2

To have R emulate LaTeX typesetting, see the examples and methods described in ?plotmath.

To actually have LaTeX typeset your plot text, use the tikz() graphics device provided by the tikzDevice package.

Answer 3

The group() plotmath function can be used to formalise DWin's answer. This solution has the advantage (IMHO) of not using strings as part of the expression. Instead we use the ~ operator to add spacing (whitespace is ignored).

plot(1:10, 1:10, type = "l", xlab = "Time t", ylab = "X",
     main=expression(Simulation ~ of ~ group("{", X[t], "}")))

The bgroup() plotmath function provides scalable delimiters but is used in the same manner as the example code above.

Edit (In response to ran2's comment): The same approaches can be used in ggplot and lattice, using the power of plotmath, just as with base graphics. E.g.

require(ggplot2)
df <- data.frame(A = 1:10, B = 1:10)
qplot(A, B, data = df,
      main = expression(Simulation ~ of ~ group("{", X[t], "}")))