Typesetting one symbolic coord differently than the others

Question

In my plots, I have one bar (labelled dummy below) whose tick label needs to be typeset differently. Here's my current attempt (and minimal example), which doesn't quite work yet:

\documentclass{article}

\usepackage{pgfplots}
\usepackage{etoolbox}

\begin{document}
\begin{tikzpicture}
\begin{axis}[
  ybar,
  symbolic x coords={foo,bar,dummy},
  xtick=data,
  xticklabel={\ifdefstrequal{\tick}{dummy}{\textcolor{gray}{\tick}}{\tick}}]
  \addplot coordinates {
    (foo,2)
    (bar,4)
    (dummy,3)
  };
\end{axis}
\end{tikzpicture}
\end{document}

Now, I definitely need matching on the symbolic x coords name; comparing the \ticknum is unfortunately not an option, as the position of the dummy bar changes from plot to plot, and I don't want to touch the definition of xticklabel each time. So is there a way to do an appropriate string comparison with \tick?

Answer 1

You could use the ifthen package:

\documentclass{article}

\usepackage{pgfplots}
\usepackage{ifthen}

\begin{document}
\begin{tikzpicture}
\begin{axis}[
  ybar,
  symbolic x coords={foo,bar,dummy},
  xtick=data,
  xticklabel=\ifthenelse{\equal{\tick}{dummy}}{\textcolor{red}{\tick}}{\tick}]
  \addplot coordinates {
    (foo,2)
    (bar,4)
    (dummy,3)
  };
\end{axis}
\end{tikzpicture}
\end{document}

---

If you want to use etoolbox, you'll have to use \ifdefstring{<macro>}{<string>}, which compares the content of a macro to a string.

\documentclass{article}

\usepackage{pgfplots}
\usepackage{etoolbox}

\begin{document}
\begin{tikzpicture}
\begin{axis}[
  ybar,
  symbolic x coords={foo,bar,dummy},
  xtick=data,
  xticklabel=\ifdefstring{\tick}{dummy}{\textcolor{red}{\tick}}{\tick}]
  \addplot coordinates {
    (foo,2)
    (bar,4)
    (dummy,3)
  };
\end{axis}
\end{tikzpicture}
\end{document}