TikZ - 计算数组为 2 个数组的最小值

Question

我定义了两个数组r和页并画出来。

我现在想计算最小值r和页以便以类似的方式绘制它。 生成的数组将是 {0.2, 0.4, 0.8, 0.8, 0.4, 0.0, 0.1, 0.0, 0.1 ,0.5}，但我想自动计算它。

你有什么主意吗 ？

以下是关于定义和绘制的 MWEr和页：

\begin{tikzpicture}
  \def\r{{0.2}, {0.4}, {1.0}, {0.8}, {1.0}, {0.0}, {0.3}, {0.5}, {0.1}, {0.5}};
  \def\p{{0.9}, {0.5}, {0.8}, {0.8}, {0.4}, {0.3}, {0.1}, {0.0}, {0.8}, {0.7}};

  \filldraw (0, 0.2) node {$r$}
    \foreach \y [count=\x from 0] in \r { -- (\x, \y) circle[radius=1pt] };
  \filldraw (0, 0.9) node {$r$}
    \foreach \y [count=\x from 0] in \p { -- (\x, \y) circle[radius=1pt] };

\end{tikzpicture}

Answer 1

基本思想是遍历第一个列表并找到第二个列表的第 n 个成员，并将最小值保存到另一个列表中。

笔记：

• 您应该避免使用单字母变量名，或者至少使用\newcommand可以检测到您正在覆盖现有宏的变量名。在这种情况下，\r是先前定义的。请参阅为什么两个具有不同名称的相同函数定义会产生两个不同的图？

参考：

• 如何保存字符串的运行列表，然后逐个处理它们
• 在 \foreach 中添加 CSV 列表时出现扩展问题

代码：

\documentclass{article}
\usepackage{tikz}

%% https://tex.stackexchange.com/questions/14393/how-keep-a-running-list-of-strings-and-then-process-them-one-at-a-time
\makeatletter
\newcommand*\@NewList{}%
\newcommand{\ApendToNewList}[1]{%
    %% https://tex.stackexchange.com/questions/83595/expansion-issue-when-adding-to-csv-list-from-within-a-foreach
    \begingroup\edef\TempValue{\endgroup%
        \noexpand\g@addto@macro\noexpand\@NewList{\ifx\@NewList\empty\else,\fi#1}}\TempValue%
}

\newcommand*{\ExtractNthValueOfList}[3]{%
    \foreach [count=\i from 1] \x in #3 {%
        \ifnum\i=#2\relax
            \xdef#1{\x}%
            \breakforeach%
         \fi
    }%
}

\newcommand*{\@NthValue}{xx}
\newcommand*{\ExtractMinList}[3]{
    % #1 = variable to contain extract list
    % #2 = first list
    % #3 = second list
    \foreach [count=\j from 1] \y in #2 {%
        \ExtractNthValueOfList{\@NthValue}{\j}{#3}%
        \pgfmathsetmacro{\MinValue}{min(\y,\@NthValue)}%
        \ApendToNewList{\MinValue}%
        \typeout{\j, \y, \@NthValue}% <--- Useful for debugging
    }%
    \edef#1{\@NewList}%
}
\makeatother


\newcommand\RList{{0.2}, {0.4}, {1.0}, {0.8}, {1.0}, {0.0}, {0.3}, {0.5}, {0.1}, {0.5}}
\newcommand\PList{{0.9}, {0.5}, {0.8}, {0.8}, {0.4}, {0.3}, {0.1}, {0.0}, {0.8}, {0.7}}
\newcommand\ExtractedMinList{}% Ensure that we are not overwriting an existing macro

\begin{document}
    \ExtractMinList{\ExtractedMinList}{\RList}{\PList}%
    Extracted List=\ExtractedMinList
\end{document}