xtable italics format for a column

Question

I need to insert the species names in a table created by xtable in my Rnw file and I want to convert the relative column to italics format. Is it possible without any manual intervention?

My call is:

xtable(cklist, caption="Checklist...", align='lllc',label = 'tab:ckzygo')

Answer 1

To typeset a column in italics (or any other non-standard font shape), you should use the >{\cmd} syntax for column specification.

Assigning the column type >{\itshape}l generates a left-justified column in italics.

This is a better solution than iris$Species <- paste0("\\textit{", iris$Species, "}") as suggested in the comments because you neither have to modify your data nor you need to disable text sanitizing.

Small illustration:

\documentclass{article}
\usepackage{array}
\begin{document}
<<xtableItalics, results = "asis">>=
library(xtable)

print(xtable(head(iris), align = c(rep("l", 5), ">{\\itshape}l")))
@
\end{document}

The PDF looks like:

Please note that you need to use the array package for this to work.

EDIT: To show the flexibility of this approach, two more examples:

print(xtable(head(iris), align = c(rep("l", 5), ">{\\textit\\bgroup}l<{\\egroup}")))
print(xtable(head(iris), align = c(rep("l", 5), ">{\\textcolor{red}\\bgroup}l<{\\egroup}")))

The first line uses \textit{} instead of \itshape to typeset the italics. As \textit{} requires the text to modify as an argument, we need a slightly more complex syntax. (It's described in the wikibooks.org article linked above.)

This syntax can also be used to change for example the color of the text. In more complex cases, lrbox is required, as described in the linked article.