error message when using nodes near coords

Question

I'm quite new to using LaTeX, I only recently visited a course about how to use it and I now have to write a code to pass this course.

Anyway, I've encountered a problem as I tried to make a bar chart for the first time. Everything went well until I inserted the option nodes near coords. I now get the error messages: (although the pdf picture looks correct)

    line 20: Undefined control sequence. \end{axis}
    line 20: Argument of \XC@definec@lor has an extra }. \end{axis}
    line 20: Paragraph ended before \XC@definec@lor was complete. \end{axis}

And this is the code I wrote so far:

\documentclass{article}
\usepackage{polyglossia}
\setmainlanguage{german}
\usepackage{pgfplotstable}
\pgfplotsset{compat=1.16}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
title={\textbf{Wie findest du den Englischunterricht?}}, 
ybar,
ymin={0},
symbolic x coords={sehr gut, gut, mittelmässig, schlecht, sehr schlecht, keine/\\ungültige\\Antwort},
width={12.58cm}, 
height={7cm},
xticklabel style={align=center},
xtick=data, 
nodes near coords
]
\addplot coordinates {(sehr gut,53) (gut,35) (mittelmässig,7) (schlecht,0) (sehr schlecht,0) (keine/\\ungültige\\Antwort,3)};
\end{axis}
\end{tikzpicture}
\end{document}

I am using XeLaTeX, TeXStudio and, as visible in the code, the pgfplots version 1.16.

So: Why am I getting these error messages and how can I fix these errors?

Thank you already for your help :)

Answer 1

There are expansion issues with the \\. Rather than playing with \noexpand, \expandafter and the like, I'd suggest to avoid these altogether.

\documentclass{article}
\usepackage{polyglossia}
\setmainlanguage{german}
\usepackage{pgfplotstable}
\pgfplotsset{compat=1.16}
\begin{document}
\begin{tikzpicture}
\begin{axis}[
title={\textbf{Wie findest du den Englischunterricht?}}, 
ybar,
ymin={0},
symbolic x coords={sehr gut, gut, mittelmässig, schlecht, sehr schlecht, 
keine/ ungültige Antwort
},
x tick label style={text width=1.5cm},
width={12.58cm}, 
height={7cm},
xticklabel style={align=center},
xtick=data, 
nodes near coords
]
\addplot coordinates {(sehr gut,53) (gut,35) (mittelmässig,7) (schlecht,0) 
(sehr schlecht,0) (keine/ ungültige Antwort,3)}; %(keine/\\ungültige\\Antwort,3)
\end{axis}
\end{tikzpicture}
\end{document}