☰

Tikz：foreach循环忽略部分边缘

tag-icon • tag-icon tikz-pgf foreach
Tikz：foreach循环忽略部分边缘

我想使用三个连续（非嵌套）的 foreach 循环绘制一些或多或少高级的网格。由于未知原因，第三个循环似乎被忽略了...以下是代码：

\begin{tikzpicture}
    \node at (22,3) (F) {$F$};

\foreach \i in {0,...,10}
{
    \pgfmathtruncatemacro{\label}{\i}
    \node at (20-2*\i,4) (A\label) {$v_{\label}$};
}

\foreach \i in {0,...,9}
{
    \pgfmathtruncatemacro{\label}{\i}
    \pgfmathtruncatemacro{\labelp}{\i + 1}
    \node at (19-2*\i,2) (E\i) {$u_{\label}$}
    (A\labelp) edge (E\label)
    (E\label) edge (A\label)
    (A\labelp) edge (A\label);
}

\foreach \i in {0,...,8}
{
    \pgfmathtruncatemacro{\label}{\i}
    \pgfmathtruncatemacro{\labelpp}{\i + 2}
    (E\label) edge[bend left = 50] (E\labelpp);
}
\end{tikzpicture}

非常感谢您的帮助！

答案1

Harald 已经评论说\draw第三个循环中缺少一个命令。因此，下一个代码只是想展示一种避免基于值的\pgfmathtruncatemacro计算的可能性。labelsindex

\documentclass[border=2mm,tikz]{standalone}

\begin{document}

\begin{tikzpicture}
\node at (22,3) (F) {$F$};

\foreach \i [count=\label from 0] in {0,...,10}
{
%    \pgfmathtruncatemacro{\label}{\i}
    \node at (20-2*\i,4) (A\label) {$v_{\label}$};
}

\foreach \i [count=\label from 0, count=\labelp] in {0,...,9}
{
%    \pgfmathtruncatemacro{\label}{\i}
%    \pgfmathtruncatemacro{\labelp}{\i + 1}
    \node at (19-2*\i,2) (E\i) {$u_{\label}$}
    (A\labelp) edge (E\label)
    (E\label) edge (A\label)
    (A\labelp) edge (A\label);
}

\foreach \i [count=\label from 0, evaluate=\label as \labelpp using \label+2] in {0,...,7}
{
%    \pgfmathtruncatemacro{\label}{\i}
%    \pgfmathtruncatemacro{\labelpp}{\i + 2}
    \draw (E\label) edge[bend left=50] (E\labelpp);
}
\end{tikzpicture}
\end{document}

在此处输入图片描述

答案2

你想要这样的东西吗？将第三个\foreach循环的边界设置为 {-1,...,7} 并添加语句\node：

\documentclass{standalone}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
    \node at (22,3) (F) {$F$};
      \foreach \i in {0,...,10}
{
    \pgfmathtruncatemacro{\label}{\i}
    \node at (20-2*\i,4) (A\label) {$v_{\label}$};
}

\foreach \i in {0,...,9}
{
    \pgfmathtruncatemacro{\label}{\i}
    \pgfmathtruncatemacro{\labelp}{\i + 1}
    \node at (19-2*\i,2) (E\i) {$u_{\label}$}
    (A\labelp) edge (E\label)
    (E\label) edge (A\label)
    (A\labelp) edge (A\label);
}

\foreach \i in {-1,...,7}
{
    \pgfmathtruncatemacro{\label}{\i}
    \pgfmathtruncatemacro{\labelpp}{\i + 2}
    \node at (17-2*\i,2) (E\label) {}
    (E\label) edge[bend left = 50] (E\labelpp);
}
\end{tikzpicture}
\end{document}

在此处输入图片描述

相关内容