\sffamily with \pgfplotstable

Question

I'm trying to create a table using pgfplotstable. It works almost fine, just asking myself why \sffamily in front of \pgfplotstabletypeset is not working.

Answer 1

The numbers in pgfplotstable are typeset in math mode. In order to influence the way they are typed you either need to load a package that changes the math fonts or use a \mathversion command. By default LaTeX only defines math versinos normal and bold. As you only need a limited number of symbols for typesetting numbers, you can set up a math version sans serif as follows:

\documentclass{article}
\usepackage{pgfplotstable}
\pgfplotsset{compat=1.8}

\DeclareMathVersion{sansserif}
\SetSymbolFont{operators}{sansserif}{OT1}{cmss}{m}{n}

\pgfplotstableread{
level   dof error1
1   4   2.50000000e-01
2   16  6.25000000e-02
3   64  1.56250000e-02
4   256 3.90625000e-03
5   1024    9.76562500e-04
6   4096    2.44140625e-04
7   16384   6.10351562e-05
8   65536   1.52587891e-05
9   262144  3.81469727e-06
10  1048576 9.53674316e-07
}\mytable

\begin{document}

\begin{minipage}[t]{0.4\linewidth}
  \pgfplotstabletypeset{\mytable}

\end{minipage}
\qquad
\begin{minipage}[t]{0.4\linewidth}
  \sffamily \mathversion{sansserif} \pgfplotstabletypeset{\mytable}
\end{minipage}

\end{document}

When \mathversion{sansserif} is in force, any operator font symbols are set to cmss, the sans serif version of computer modern. (lmss would be an obviosu alternative if using latin modern fonts). Now we can switch to sans serif for text via \sffamily and for math via \mathversion{sansserif}. Switch back with \normalfont and \mathversion{normal}.

Answer 2

pgfplotstable relies on LaTeX's famous math mode to typeset its numbers. This, in turn, does not work with \sffamily.

That said, I am always a little bit confused of what the actual answer is as I never really understood the details of math fonts. If I am not mistaken, one has to add some special \usepackage instruction to replace math fonts throughout the document. But I hope that I am wrong.

Perhaps you should search for the answers to the question "How can I use sans serif fonts in math mode" -- the answer is applicable here as well.