latex2exp R Package

The latex2exp package allows you to use LaTeX syntax in R plots by parsing and converting LaTeX strings into R's native plotmath expressions.

Converted expressions can be used for any part of the R plotting system that accepts mathematical expressions, including:

• Axis labels
• Annotations
• Legends
• Plot titles

You can install latex2exp from CRAN or the development version from GitHub.

To install the stable version from CRAN:

install.packages('latex2exp')

To install the development version from GitHub using devtools:

devtools::install_github('stefano-meschiari/latex2exp')

You can use TeX() for xlab, ylab, main, and legend arguments in base R plotting functions.

x <- seq(0, 4, length.out=100)
alpha <- 1:5

plot(x, xlim=c(0, 4), ylim=c(0, 10), 
     xlab='x', ylab=TeX(r'($\alpha  x^\alpha$, where $\alpha \in \{1 \ldots 5\}$)'), 
     type='n', main=TeX(r'(Using $\LaTeX$ for plotting in base graphics!)', bold=TRUE))

for (a in alpha) {
  lines(x, a*x^a, col=a)
}

legend('topleft', 
       legend=TeX(sprintf(r'($\alpha = %d$)', alpha)), 
       lwd=1, 
       col=alpha)

In ggplot2, TeX() can be used within ylab(), ggtitle(), and scale_*_discrete(labels=...).

Important Note: When using scale_*_discrete to provide labels, ggplot2 requires the labels to be a list of expressions, not a vector of expressions. Use lapply() to wrap the TeX() calls.

x <- seq(0, 4, length.out=100)
alpha <- 1:5
data <- map_df(alpha, ~ tibble(v=.*x^., x=x, alpha=.))

p <- ggplot(data, aes(x=x, y=v, color=as.factor(alpha))) +
    geom_line() +
    ylab(TeX(r'($\alpha  x^\alpha$, where $\alpha \in 1\ldots 5$)')) +
    ggtitle(TeX(r'(Using $\LaTeX$ for plotting in ggplot2. I $\heartsuit$ ggplot!)')) +
    coord_cartesian(ylim=c(-1, 10)) +
    guides(color=guide_legend(title=NULL)) +
    scale_color_discrete(labels=lapply(sprintf(r'($\alpha = %d$)', alpha), TeX)) 

print(p)

You can run the latex2exp_examples() function to see a visual gallery of supported LaTeX commands and their translations.

latex2exp_examples(cex=0.9)

To quickly see how a LaTeX string will be rendered as a plotmath expression, pass the TeX() output to the plot() function.

plot(TeX(r'(A $\LaTeX$ formula: $\frac{2hc^2}{\lambda^5}\frac{1}{e^{\frac{hc}{\lambda k_B T}} - 1}$)'), cex=2, main="")

The TeX() function is the core API of the package. It takes a LaTeX string, parses it, and returns the closest R plotmath expression. The resulting expression can be used in axis labels, legends, titles, and annotations for both base R graphics and ggplot2.

# Using R 4.0+ raw string syntax (recommended)
TeX(r"(\textbf{Euler's identity} is $e^{i\pi} + 1 = 0$.")

# Using regular strings (requires escaping backslashes)
TeX("\\textbf{Euler's identity} is $e^{i\\pi} + 1 = 0$.")