☰

如何确定数组的大小？

tag-icon • tag-icon tikz-pgf arrays
如何确定数组的大小？

经过长时间的搜索，我仍然无法弄清楚如何确定和使用len这样的数组：

\def\mar{ 1,2 }
\path let \p1=($(rec.west)-(rec.east)$),
              \p2=($(rec.north)-(rec.south)$),
              \p3=($len{\mar}$),
              \n1 = {veclen(\p1)*0.16}                  %width
              ,\n2 = {veclen(\p2)/\p3}                    %height
              in node[mynode,
                      minimum width=\n1
                      ,minimum height=\n2
                      ,anchor=north west
                      ] at (rec.north west) {foobar
                      };

答案1

我不知道 TikZ 中是否有数组长度计数器（它可能在 CVS 版本中引入）。因此，请向xstring包中，我们计算逗号并添加一。

\documentclass{article}
\usepackage{tikz,xstring}
\usetikzlibrary{calc}
\def\mar{1,2,4,5,7}
\StrCount{\mar}{,}[\arrlength]

\begin{document}
\begin{tikzpicture}
\node[draw,minimum width=2cm,minimum height=5cm] (rec) at (2cm,1cm) {rec};
\path let \p1=($(rec.west)-(rec.east)$),
              \p2=($(rec.north)-(rec.south)$),
              \n{arrlen}={\arrlength+1},
              \n1 = {veclen(\p1)*0.16},           %width
              \n2 = {veclen(\p2)/\n{arrlen}}      %height
              in node[draw,
                      minimum width=\n1
                      ,minimum height=\n2
                      ,anchor=north west
                      ] at (rec.north west) {foobar
                      };
\end{tikzpicture}
I have found \arrlength\space commas in the array.
\end{document}

在此处输入图片描述

答案2

就像 PolGab 在他的评论中所写的那样，你有一些可能性可以将数组与 pgfmath 一起使用。以下是来自 pgfmanual 的一些示例：

\def\myarray{{7,-3,4,-9,11}}
\pgfmathparse{\myarray[3]} \pgfmathresult

\def\print#1{\pgfmathparse{#1}\pgfmathresult}
\def\identitymatrix{{{1,0,0},{0,1,0},{0,0,1}}}
\tikz[x=0.5cm,y=0.5cm]\foreach \i in {0,1,2} \foreach \j in {0,1,2}
  \node at (\j,-\i) [anchor=base] {\print{\identitymatrix[\i][\j]}};

  \pgfmathparse{array({9,13,17,21},2)} \pgfmathresult

坏消息： len数组的 不存在于 pgfmath 中。将这种可能性添加到 pgfmath 中并不复杂。这是一种无需新包的简单方法。它不是很有效，但很简单。

\documentclass[11pt]{scrartcl}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}

\def\getlen#1{%
\pgfmathsetmacro{\lenarray}{0}% 
\foreach \i in #1{%
\pgfmathtruncatemacro{\lenarray}{\lenarray+1}% 
\global\let\lenarray\lenarray}%
}   

  \begin{tikzpicture}
    \node[draw,minimum width=2cm,minimum height=5cm,fill=blue!30,opacity=.5 ] (rec) at (2cm,1cm) {REC};
    \def\mar{1,2}
    \getlen{\mar} 
\path let \p1=($(rec.west)-(rec.east)$),
          \p2=($(rec.north)-(rec.south)$),
          \n1 = {veclen(\p1)*0.16},
          \n2 = {veclen(\p2)/\lenarray}
              in node[draw,minimum width  = \n1,
                      minimum height = \n2,
                      anchor=north west,fill=orange!30,opacity=.5
                      ] at (rec.north west) {foobar};
  \end{tikzpicture}   

\end{document}

在此处输入图片描述

答案3

下面使用\foreach循环来计算成员数，并忽略由于多余逗号而导致的空成员。因此，对于如下定义

\def\mar{1,2 , 4,, 5 ,7,,,}

本报告有 5 名成员：

在此处输入图片描述

代码：

\documentclass{article}
\usepackage{tikz}
\usepackage{xstring}
\usetikzlibrary{calc}

\def\mar{1,2 , 4,, 5 ,7,,,}

\makeatletter
\newcounter{@LengthOfArray}%
\newcommand{\GetArrayLength}{\arabic{@LengthOfArray}}%
\newcommand*{\SetArrayLength}[1]{%
    % Counts the number of array members. This ignore any empty
    % array members created by extraneous commas (such as those
    % as  result of a double comma, or a trailing comma.
    \setcounter{@LengthOfArray}{0}%
    \foreach \x in #1 {%
        \IfStrEq{\x}{}{}{% only increment when non-empty
            \stepcounter{@LengthOfArray}%
        }%
    }%
}%
\makeatother


\begin{document}
\SetArrayLength{\mar}
\begin{tikzpicture}
\node[draw,minimum width=2cm,minimum height=5cm] (rec) at (2cm,1cm) {rec};
\path let \p1=($(rec.west)-(rec.east)$),
              \p2=($(rec.north)-(rec.south)$),
              \n{arrlen}={\GetArrayLength},
              \n1 = {veclen(\p1)*0.16},           %width
              \n2 = {veclen(\p2)/\n{arrlen}}      %height
              in node[draw,
                      minimum width=\n1
                      ,minimum height=\n2
                      ,anchor=north west
                      ] at (rec.north west) {foobar
                      };
\end{tikzpicture}

\Large
There are \GetArrayLength\space members in the array.
\end{document}

相关内容