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如何中断/暂停和继续链式传输

tag-icon • tag-icon tikz-pgf tikz-chains
如何中断/暂停和继续链式传输

我需要说明一个链接列表和添加一个元素，有没有什么方法可以停止并继续 foreach 循环或暂停链，这样它就不会连接元素 5 和 6？

\documentclass{article}
\usepackage{pgffor}
\usepackage{tikz}
\usepackage{xfp}
\usepackage{mathtools}
\usetikzlibrary{calc, shapes.multipart,chains,arrows,positioning}

\tikzstyle{strela} = [thick, ->, >=stealth]

\newcommand\x{9}
\newcommand\y{3}
\newcommand\m{5}

\begin{document}
    
    \begin{tikzpicture}[ar/.style={*->,shorten <=-.28cm},list/.style={rectangle split, rectangle split parts=2, draw, rectangle split horizontal,join=by ar}, start chain=going right]
        
                    
            \foreach \i in {3,...,\the\numexpr\x}{
                \node[list,on chain] (\the\numexpr\i) {\i};         
            }  
            \node (strela2) [strela, below of= 3,  xshift=-0.5cm, yshift=-0.7cm]{HEAD};
            \draw (strela2) -> (3); 
            
            \node (strela3) [strela, below of= \the\numexpr\x,  xshift=-0.5cm, yshift=-0.7cm] {TAIL};
            \draw (strela3) -> (\the\numexpr\x);
            
            \node (obj) [right of= \the\numexpr\x,draw,inner sep=6pt] (D) {};
            \draw (D.north east) -- (D.south west);
            \draw (D.north west) -- (D.south east);
            
            \draw [*->, shorten <=+.10cm] (\the\numexpr\x.center) -- (D);
            
            \node (strela5) [strela, below of= D, yshift=-0.72cm] {NULL};
            \draw (strela5) -> (D);

      \node[list,below of= \the\numexpr\m, xshift=+1cm] (A) {\the\numexpr\m+0.5};
        
        
        
    \end{tikzpicture}
    
    \begin{flushleft}
        \vspace{2cm}        
    
    \end{flushleft}

    \begin{tikzpicture}[ar/.style={*->,shorten <=-.28cm},list/.style={rectangle split, rectangle split parts=2, draw, rectangle split horizontal,join=by ar}, start chain=going right]
    
    
    \foreach \i in {3,...,\the\numexpr\x/2}{
        \node[list,on chain] (\the\numexpr\i) {\i};         
    } 
    

    \node[list,below of= \the\numexpr\m, xshift=+1cm] (A) {\the\numexpr\m+0.5};

   
    \draw[*->] let \p1 = (\the\numexpr\m.two), \p2 = (\the\numexpr\m.center) in (\x1,\y2) -- (A);
   
    \draw[*->] let \p1 = (A.two), \p2 = (A.center) in (\x1,\y2) -- (\the\numexpr\m+1);
    
 
    \foreach \k in {\the\numexpr\x/2 + 1,...,\the\numexpr\x}{
    \node[list, on chain] (\the\numexpr\i) {\k};            
}   

    \node (strela2) [strela, below of= 3,  xshift=-0.5cm, yshift=-0.7cm]{HEAD};
    \draw (strela2) -> (3); 

\end{tikzpicture}
\end{document}

答案1

您可以测试当前号码并根据此测试添加连接。

与您的问题无关：不要使用已弃用的\tikzstyle，您可以改用\tikzset。

\documentclass{article}
\usepackage{pgffor}
\usepackage{tikz}
\usepackage{xfp}
\usepackage{mathtools}
\usetikzlibrary{calc, shapes.multipart,chains,arrows,positioning}

\tikzset{strela/.style={thick, ->, >=stealth}}

\newcommand\x{9}
\newcommand\y{3}
\newcommand\m{5}

\begin{document}
    
    \begin{tikzpicture}[ar/.style={*->,shorten <=-.28cm},list/.style={rectangle split, rectangle split parts=2, draw, rectangle split horizontal}, start chain=going right]
        
                    
            \foreach \i in {3,...,\the\numexpr\x}{
              \ifnum\i=6
                \node[list,on chain] (\the\numexpr\i) {\i};
              \else
                \node[list,on chain,join=by ar] (\the\numexpr\i) {\i};         
              \fi
            }  
        
        
    \end{tikzpicture}


\end{document}

在此处输入图片描述

答案2

解决方案 1

\foreach \i in {3, ..., 9}
  \node[list, on chain,
    /utils/TeX/ifnum={\i=6}{}{join=by ar}
  ] {\i};

与 samcarter 的答案类似，它只是移动\ifnum节点内部的选项，这样您就不必编写冗余代码。

没有ext.misc你也可以达到几乎相同的效果

\node[list, on chain, style/.expanded={\ifnum\i=6 \else join=by ar\fi}] {\i};

但有点乱。

样式ar*定义为

ar*/.style={
  to path={[insert path/.expanded={
      edge[path only, line to]
        node[list,below=5mm] (@) {\unexpanded{#1}} (\tikztotarget)
      (\tikztostart) edge[ar] (@)
      (@) edge[ar] (\tikztotarget)}]}}

你可以做

\node[list, on chain,
  /utils/TeX/ifnum={\i=6}{join=by {ar*={5,5}}}{join=by ar}
] {\i};

甚至得到

在此处输入图片描述

不需要做太多工作（不过，我建议增加text depth=0pt风格list）。

解决方案 2 只是尝试了一些可能会禁用该join键的样式。这也意味着join?=\i（或只是kill join \i/.try）需要在实际join键之前。（不幸的是，没有“干净”的方法来脱离节点但这看起来很简单。

处理程序允许您快速给出不应该加入.list的列表。\i

ar*相反，仅使用非常具体的依赖键可能同样可以添加连接\i。

代码

\documentclass[varwidth]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc, shapes.multipart, chains, arrows.meta}
\tikzset{every picture/.append style={
  node distance=5mm,
  */.tip={Circle[sep=-1.196825pt -1.595769]},
  ar/.style={*->, to path={($(\tikztostart.two south)!.5!(\tikztostart.two north)$) -- (\tikztotarget)}},
  ar*/.style={
    to path={[insert path/.expanded={
        edge[path only, line to]
          node[list,below=5mm] (@) {\unexpanded{##1}} (\tikztotarget)
        (\tikztostart) edge[ar] (@)
        (@) edge[ar] (\tikztotarget)}]}},
  list/.style={rectangle split, rectangle split parts=2, draw, rectangle split horizontal},
  start chain=going right}}

% Solution 1:
\usetikzlibrary{ext.misc}

% Solution 2:
\tikzset{
  join?/.style={kill join on #1/.try},
  don't join on/.style={
    kill join on #1/.style={join/.code=}}}
    
\begin{document}
% Solution 1:
\tikz\foreach \i in {3, ..., 9}
  \node[list, on chain,
    /utils/TeX/ifnum={\i=6}{join=by {ar*={5,5}}}{join=by ar}
  ] {\i};
\\

% Solution 1 without ext.misc
\tikz\foreach \i in {3, ..., 9}
  \node[list, on chain, style/.expanded={\ifnum\i=6 \else join=by ar\fi}] {\i};
\\

% Solution 2:
\tikz[don't join on=6]\foreach \i in {3, ..., 9}
  \node[list, on chain, join?=\i, join=by ar] {\i};
\\

% Solution 2 with more than one:
\tikz[don't join on/.list={4,6,8}]\foreach \i in {3, ..., 9}
  \node[list, on chain, join?=\i, join=by ar] {\i};
\end{document}

输出

在此处输入图片描述

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