如何在两个条形图之间留出空间

Question 1

我建议看看pgfplots 手册（5.8 分组图）。斜体段落直接取自手册。

1. 空间

和

group/horizontal sep=<dimension>
group/vertical sep=<dimension>

我们设置分别表示水平和垂直方向上绘图之间的间距。如果您希望将它们粘合在一起，则应将它们的长度都设置为 0pt。

2.X 标签

和

group/x descriptions at=all|edge top|edge bottom
group/y descriptions at=all|edge left|edge right

我们可以设置 x 和 y 标签的位置。这些只是同时使用 xticklabels at 和 xlabels at 的简写。问题是我们将标题放在上面，将图例放在下面。所以我们只能将 x 标签放在每个 x 轴的右侧。为此，我们首先group/group name={<name>}在groupplot环境中进行设置。之后我们可以参考情节：

% bar chart 1
\node[xshift=.75cm, yshift=-.2cm] at (myResults c1r1.south east) {x-Label};
% bar chart 2
\node[xshift=.75cm, yshift=-.2cm] at (myResults c2r1.south east) {x-Label};

3. 标题

title={<title>}要设置标题，我们可以向每个标题添加选项\nextgroupplot。

完整代码：

\documentclass[tikz]{standalone}
\usepackage{pgfplots}
\usepgfplotslibrary{groupplots}

\pgfplotsset{compat=1.16}


\begin{document}
\begin{tikzpicture}
    \begin{groupplot}[group style={group name=myResults, group size=2 by 1, horizontal sep=2.5cm},width=12cm,height=8cm, ylabel = {y}]
        \nextgroupplot[
            title={Title 1},
            %legend style={at={(mygroup.south)},anchor=north,legend columns=-1},
            symbolic x coords={Precision,Recall,F1-Score,Accuracy},
            major tick length=0cm,
            xtick=data,
            ymin=50.0,
            enlarge x limits=0.2,
            enlarge y limits={upper,value=0.2},
            nodes near coords,
            ybar,
            every node near coord/.append style={rotate=90, anchor=west},
            bar width = 8pt
        ]

        \addplot coordinates {(Precision,86.6) (Recall,86.0) (F1-Score,86.3) (Accuracy,98.4)};
        \addplot coordinates {(Precision,87.6) (Recall,86.2) (F1-Score,86.5) (Accuracy,97.5)};
        \addplot coordinates {(Precision,85.9) (Recall,86.3) (F1-Score,86.1) (Accuracy,98.6)};
        \addplot coordinates {(Precision,87.1) (Recall,86.8) (F1-Score,87.0) (Accuracy,99.2)};
        \addplot coordinates {(Precision,85.5) (Recall,82.8) (F1-Score,83.7) (Accuracy,97.4)};
        \addplot coordinates {(Precision,77.9) (Recall,77.7) (F1-Score,75.9) (Accuracy,87.8)};
        %\legend{KNN,Neural Networks,Decision Tree,Random Forest,SVM,Naive Bayes}

        \nextgroupplot[
            title={Title 2},
            legend style={at={(-\pgfkeysvalueof{/pgfplots/group/horizontal sep}/2,-0.1)},
                    anchor=north,legend columns=-1},
            symbolic x coords={Precision,Recall,F1-Score,Accuracy},
            major tick length=0cm,
            xtick=data,
            ymin=50.0,
            enlarge x limits=0.2,
            enlarge y limits={upper,value=0.2},
            nodes near coords,
            ybar,
            every node near coord/.append style={rotate=90, anchor=west},
            bar width = 8pt,
        ]

        \addplot coordinates {(Precision,86.6) (Recall,86.0) (F1-Score,86.3) (Accuracy,98.4)};
        \addplot coordinates {(Precision,87.6) (Recall,86.2) (F1-Score,86.5) (Accuracy,97.5)};
        \addplot coordinates {(Precision,85.9) (Recall,86.3) (F1-Score,86.1) (Accuracy,98.6)};
        \addplot coordinates {(Precision,87.1) (Recall,86.8) (F1-Score,87.0) (Accuracy,99.2)};
        \addplot coordinates {(Precision,85.5) (Recall,82.8) (F1-Score,83.7) (Accuracy,97.4)};
        \addplot coordinates {(Precision,77.9) (Recall,77.7) (F1-Score,75.9) (Accuracy,87.8)};
        



        \legend{KNN,Neural Networks,Decision Tree,Random Forest,SVM,Naive Bayes}
    \end{groupplot}

    % x axis label
    \node[xshift=.75cm, yshift=-.2cm] at (myResults c1r1.south east) {x-Label};
    \node[xshift=.75cm, yshift=-.2cm] at (myResults c2r1.south east) {x-Label};
\end{tikzpicture}

\end{document}

Answer