# Table input in tikzpicture with scatter classes

I'm getting the error message:

! Package PGF Math Error: Could not parse input 'a' as a floating point number, sorry. The unreadable part was near 'a'..

Somehow the table cannot be read. I would like to have an axis with colored points on them. The first part worked until I added the scatter/classes and table thing.

\documentclass{article}
\usepackage{tikz, pgfplots}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}[scale=1.5]
\begin{axis}[
axis x line=center,
axis y line=none,
hide y axis,
xmin=0,xmax=20,
ymin=0, ymax=1,
xtick={0,...,20},
xticklabels={,,}
scatter/classes={%
a={mark=o,draw=blue},
b={mark=o,draw=red}}]

scatter src=explicit symbolic]%
table[meta=label]{
x   label
1   a
2   a
3   a
4   a
6   a
13  a
10  b
14  b
17  b
18  b
};
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}


Working example without a plot:

\documentclass{article}
\usepackage{tikz, pgfplots}

\begin{document}

\begin{figure}
\centering
\begin{tikzpicture}[scale=1.5]
\begin{axis}[
axis x line=center,
axis y line=none,
hide y axis,
xmin=0,xmax=20,
ymin=0, ymax=1,
xtick={0,...,20},
xticklabels={,,},
scatter/classes={%
a={mark=o,draw=blue},
b={mark=o,draw=red}}]
\end{axis}
\end{tikzpicture}
\end{figure}

\end{document}

• Welcome to TeX.SX! Please make your code compilable (if possible), or at least complete it with \documentclass{...}, the required \usepackage's, \begin{document}, and \end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. – dexteritas Jul 28 '17 at 14:06
• You need to add a y column consisting of 0. – Symbol 1 Jul 28 '17 at 15:13
• @Symbol1 unfortunately the same error persists – rattletat Jul 28 '17 at 15:31
• And also at the end of xticklabels={,,} you missed a comma. – Symbol 1 Jul 28 '17 at 15:43
• @Symbol1 Thank you!! That fixed it. – rattletat Jul 28 '17 at 16:09

@Symbol1 fixed this in the comments. Here's the working code.

\documentclass{article}
\usepackage{tikz, pgfplots}
\begin{document}
\begin{figure}
\centering
\begin{tikzpicture}[scale=1.5]
\begin{axis}[
axis x line=center,
axis y line=none,
hide y axis,
xmin=0,xmax=20,
ymin=0, ymax=1,
xtick={0,...,20},
xticklabels={,,},
scatter/classes={%
a={mark=o,draw=blue},
b={mark=o,draw=red}}]

scatter src=explicit symbolic]%
table[meta=label]{
x   y   label
1   0   a
2   0   a
3   0   a
4   0   a
6   0   a
13  0   a
10  0   b
14  0   b
17  0   b
18  0   b
};
\end{axis}
\end{tikzpicture}
\end{figure}
\end{document}