[Tex/LaTex] Bar chart with PGFPlots: Two groups with two categories and two bars each

bar chartpgfplots

Using \pgfplots, I have a bar chart that looks like this:
enter image description here

Instead, I would like to have something like this, so that I have two groups ("Freie Wiedergabe Tag 1" and "Freie Wiedergabe Tag 2") in 2 categories ("Erinnert" and "Nicht erinnert") and with two bars ("neutral" and "negativ") each. I have no idea how to do this:

enter image description here

My MWE is here:

\documentclass{apa6}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\usetikzlibrary{arrows.meta}
\begin{document}
\begin{figure}
\begin{tikzpicture}[scale=1.6,transform shape]
\begin{axis}[
ybar,
enlargelimits=0.15,
legend style={at={(0.5,-0.25)},
anchor=north,legend columns=-1},
ylabel={Anteil},
symbolic x coords={Freie Wiedergabe Tag 1,Freie Wiedergabe Tag 2,Treffer,Falscher Alarm},
xtick=data,
xticklabel style={text width=1.5cm,
font=\tiny,
align=center
},
]
%neutral
\addplot[blue,fill=blue!30!white,error bars/.cd,y dir=both,y explicit,]
coordinates{(Treffer,0.8560) +-(0.01503,0.01503) (Falscher Alarm,0.1390) +-(0.01737,0.01737)(Freie Wiedergabe Tag 1,0.1481) +-(0.01067,0.01067) (Freie Wiedergabe Tag 2,0.1119) +-(0.00922,0.00922) };
%negativ
\addplot[red,fill=red!30!white,error bars/.cd,y dir=both,y explicit,]
coordinates {(Treffer,0.9365) +- (0.00587,0.00587)(Falscher Alarm,0.1435) +- (0.01737,0.01737)(Freie Wiedergabe Tag 1,0.3247) +-(0.01695,0.01695) (Freie Wiedergabe Tag 2,0.2556) +-(0.01524,0.01524)
};
\legend{neutral,negativ}
\end{axis}
\end{tikzpicture}
\caption{Unterschrift}
\label{GedaechtnisBilder}
\end{figure}
\end{document}

Best Answer

The data points are probably not in the correct place, but apart from that one way of achieving that is shown below. I've changed the coordinates to numerical x-values (1,2,3,4) instead of symbolic coordinates, and set xticklabels={Erinnert,Nicht erinnert,Erinnert,Nicht erinnert}. So the four data points in each \addplot should correspond to those categories, the first two for the first day, the last two for the second day.

Then I've added two extra x ticks={1.5,3.5} (midway between the two groups of bars), with extra x tick labels={Freie Wiedergabe Tag 1,Freie Wiedergabe Tag 2}. Some vertical shifting of the ticklabels is done.

output of code

\documentclass{apa6}
\usepackage{pgfplots}
\pgfplotsset{compat=1.13}
\usetikzlibrary{arrows.meta}
\begin{document}
\begin{figure}
\begin{tikzpicture}
\begin{axis}[
% instead of scaling
width=0.6\linewidth,
ybar,
enlargelimits=0.15,
legend style={
% to save space I would place the legend inside the axis, at least with these data
  %at={(0.5,-0.2)},
  %anchor=north,
legend columns=-1},
ylabel={Anteil},
ylabel style={font=\large},
xtick=data,
% use explicit ticklabels instead of symbolc x coords
xticklabels={Erinnert,Nicht erinnert,Erinnert,Nicht erinnert},
xticklabel style={
%  text width=2cm,
  yshift=-18pt, % move xticks down a bit
%  align=center
},
% extra ticks
extra x ticks={1.5,3.5},
extra x tick labels={Freie Wiedergabe Tag 1,Freie Wiedergabe Tag 2},
extra x tick style={
  % because the xticklabel style also affects the extra ticks, 
  % shift extra ticklabels back up
  ticklabel style={yshift=13pt},
  % tickwidth is actually the length of of the ticks (the small lines)
  tickwidth=0
}
]
%neutral
\addplot[blue,fill=blue!30!white,error bars/.cd,y dir=both,y explicit,]
coordinates{
   (1,0.8560) +-(0.01503,0.01503)
   (2,0.1390) +-(0.01737,0.01737)
   (3,0.1481) +-(0.01067,0.01067)
   (4,0.1119) +-(0.00922,0.00922)
};
%negativ
\addplot[red,fill=red!30!white,error bars/.cd,y dir=both,y explicit,]
coordinates {
  (1,0.9365) +- (0.00587,0.00587)
  (2,0.1435) +- (0.01737,0.01737)
  (3,0.3247) +-(0.01695,0.01695)
  (4,0.2556) +-(0.01524,0.01524)
};
\legend{neutral,negativ}
\end{axis}
\end{tikzpicture}
\caption{Unterschrift}
\label{GedaechtnisBilder}
\end{figure}
\end{document}
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