在图例中添加其他文本

Question

我正在学习 Tikz/Pgfplots，并尝试重新创建以下图表

到目前为止，我已经能够得出以下结论：

    \begin{tikzpicture}
      \begin{axis}[axis lines = center, axis equal image,
          domain = -2.5:2.5,
          ymax=4.5,
          tick label style = {font=\scriptsize},
          xtick = {0, 1},
          xticklabels = {0, 1},
          legend entries = {$a^x$, $b^x$},
          ytick = {0.5, 1, 2},
          yticklabels = {b, 1, a},
          xlabel= \(x\),
          ylabel= \(y\),
          legend style={at={(0.03,0.3)},anchor=west},
          font=\scriptsize]
        \addplot[red, name path=expg1] {2^x};
        \addplot[blue, name path=expl1] {0.5^x};
        \node[fill,circle,inner sep=1pt,label={right:$(1,a)$}] at
    (1,2){};
        \node[fill,circle,inner sep=1pt,label={right:$(1,b)$}] at
    (1,0.5){};
        \draw[dashed,help lines] (1,0) -- (1,2);
        \draw[dashed,help lines] (1,2) -- (0,2);
        \draw[dashed,help lines] (1,0.5) -- (0,0.5);
      \end{axis}
    \end{tikzpicture}

结果是：

这很好，但我无法在图例中添加信息“a>1”和“0<b<1”：当我尝试修改

    legend entries = {$a^x$, $b^x$}

到图例条目 = {$a^x, a>1$, $b^x, 0<b<1$}

该文件无法编译（我使用的是 Overleaf），而且我还没能找到其他方法来添加此信息。所以，如果有人能向我解释如何做到这一点，我将不胜感激。谢谢。

Answer 1

您需要“保护”,选项解析器的内部逗号 --- 只需将每个条目括在附加括号之间即可。

我还添加了一些代码来改变框中标签的排列（图例样式中的部分）以及数学模式下逗号后的nodes={...}明确空格。\;

\documentclass{article}
\usepackage{pgfplots}\pgfplotsset{compat=1.18}
\usetikzlibrary{intersections}

\begin{document}

  \begin{tikzpicture}
      \begin{axis}[axis lines = center, axis equal image,
          domain = -2.5:2.5,
          ymax=4.5,
          tick label style = {font=\scriptsize},
          xtick = {0, 1},
          xticklabels = {0, 1},
          legend entries = {{$a^x,\;a>0$}, {$b^x,\; 0<b<1$}},
          ytick = {0.5, 1, 2},
          yticklabels = {b, 1, a},
          xlabel= \(x\),
          ylabel= \(y\),
          legend style={at={(0.03,0.3)},anchor=west,nodes={right, font=\scriptsize}},
          font=\scriptsize]
        \addplot[red, name path=expg1] {2^x};
        \addplot[blue, name path=expl1] {0.5^x};
        \node[fill,circle,inner sep=1pt,label={right:$(1,a)$}] at (1,2){};
        \node[fill,circle,inner sep=1pt,label={right:$(1,b)$}] at (1,0.5){};
        \draw[dashed,help lines] (1,0) -- (1,2);
        \draw[dashed,help lines] (1,2) -- (0,2);
        \draw[dashed,help lines] (1,0.5) -- (0,0.5);
      \end{axis}
    \end{tikzpicture}
\end{document}

PS，下次，请避免发布不完整的代码片段：在其周围添加样板，以便人们可以复制并粘贴它，然后进行编译。