Groupplots/Pgfplots: How can I change the x-positions of the bars in a bar chart?

Question

I'm trying to create a tikzpicture, composed of 2 separate diagrams. I'm using the \usepgfplotslibrary{groupplots} package for this. All is going fine, but I cannot seem to get the bars to a more central position (see image: they're currently at the very corners of the plot).

This is a minimal working example:

\documentclass{article}
\usepackage{pgfplots}
\usepgfplotslibrary{groupplots}
\usepackage{tikz}
\usetikzlibrary{matrix}
\pgfplotsset{compat=newest}
\begin{document}
\begin{tikzpicture}
    \begin{groupplot}[
        group style={group size= 2 by 1},
        height=8cm,
        width=5cm,
        ymax=100,
        ymin=0,
        ybar,
        xtick=data,
        x tick label style={rotate=45,anchor=east}
        ]
        \nextgroupplot[title=A,legend to name=zelda, symbolic x coords={Class3, Class4}, bar width=9pt]
            \addplot+[ybar, draw=red, fill=red] plot coordinates {
            (Class3, 60.83)
            (Class4, 54.83)
            }; 
            \addlegendentry{(Both) correct};
            \addplot+[ybar, draw=blue, fill=blue] plot coordinates {
            (Class3, 37.00)
            (Class4, 42.17)
            };
            \addlegendentry{One correct};
            \coordinate (top) at (rel axis cs:0,1);% coordinate at top of the first plot
        \nextgroupplot[title=B, symbolic x coords={Class1, Class2}, bar width=9pt]
            \addplot+[ybar, draw=red, fill=red] plot coordinates {
            (Class1,89.00)
            (Class2,87.00)
            };
            \coordinate (bot) at (rel axis cs:1,0);% coordinate at bottom of the last plot
    \end{groupplot}
    \path (top)--(bot) coordinate[midway] (group center);
    \node[above,rotate=90] at (group center -| current bounding box.west) {Accuracy};
    \node[right=1em,inner sep=0pt] at(group center -| current bounding box.east {\pgfplotslegendfromname{zelda}};
\end{tikzpicture}
\end{document}

Any help would be highly appreciated.

Answer 1

Turns out, enlarge x limits did the trick. This makes it necessary to change the symbolic coords to xtick={1,2}, and then add enlarge x limits=0.5 to the \nextgroupplot section

Full code:

\documentclass{article}
\usepackage{pgfplots}
\usepgfplotslibrary{groupplots}
\usepackage{tikz}
\usetikzlibrary{matrix}
\pgfplotsset{compat=newest}
\begin{document}
\begin{tikzpicture}
    \begin{groupplot}[
        group style={group size= 2 by 1},
        height=8cm,
        width=5cm,
        ymax=100,
        ymin=0,
        ybar,
        xtick={1,2},
        x tick label style={rotate=45,anchor=east}
        ]
        \nextgroupplot[title=A,legend to name=zelda, xticklabels={Class3, Class4}, bar width=9pt, enlarge x limits=0.5]
            \addplot+[ybar, draw=red, fill=red] plot coordinates {
        (Class3, 60.83)
        (Class4, 54.83)
        }; 
            \addlegendentry{(Both) correct};
            \addplot+[ybar, draw=blue, fill=blue] plot coordinates {
        (Class3, 37.00)
        (Class4, 42.17)
        };
            \addlegendentry{One correct};
            \coordinate (top) at (rel axis cs:0,1);% coordinate at top of the first plot
        \nextgroupplot[title=B, xticklabels={Class1, Class2}, bar width=9pt, enlarge x limits=0.5]
            \addplot+[ybar, draw=red, fill=red] plot coordinates {
        (Class1,89.00)
        (Class2,87.00)
        };
            \coordinate (bot) at (rel axis cs:1,0);% coordinate at bottom of the last plot
\end{groupplot}
\path (top)--(bot) coordinate[midway] (group center);
\node[above,rotate=90] at (group center -| current bounding box.west) {Accuracy};
\node[right=1em,inner sep=0pt] at(group center -| current bounding box.east {\pgfplotslegendfromname{zelda}};
\end{tikzpicture}
\end{document}