在 for 循环中提供交替整数

Question

以下代码打印标签富，酒吧，巴兹， 和積極在圆的交替两侧。这是通过对 中指定的多个变量进行 for 循环来实现的\myInput。负责这些标签的垂直放置（即它们与中心 [0,0] 的距离）的变量是varC。

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}

\def \CircleIntervals {0,90,...,270}
\def \myInput {
    foo/45/2/red,
    bar/135/4/green,
    baz/225/2/blue,
    qux/315/4/brown}

\begin{document}
    \begin{tikzpicture}[line cap=rect, line width=3pt]
    \draw[] (0,0) circle [radius=3cm];
    \foreach \angle [count=\xi] in \CircleIntervals
    {
        \draw[line width=1.5pt] (\angle:2.9cm) -- (\angle:3.1cm);
        \node[] at (\angle:3.5cm) {\xi};
    }
    \foreach \varA/\varB/\varC/\varD in \myInput {
        \node[color=\varD] at (\varB:\varC cm) {\Large{\varA}};
    }
    \end{tikzpicture}
\end{document}

由于varC只提供重复模式，我不希望它成为的一部分\myInput，而是将其硬编码为循环的一部分。

我如何修改第二个循环，使得整数2和4是按连续重复的顺序提供的吗？

Answer 1

一种或多或少“基本”的方法

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}

\def \CircleIntervals {0,90,...,270}
\def \myInput {
  foo/45/red,
  bar/135/green,
  baz/225/blue,
  qux/315/brown}

\newif\ifdothis

\def\foostate{%
  2%
}

\newcommand{\togglefoostate}{%
  \ifdothis
  \gdef\foostate{2}
  \global\dothisfalse
  \else
  \gdef\foostate{4}
  \global\dothistrue
  \fi
}


\begin{document}
    \begin{tikzpicture}[line cap=rect, line width=3pt]
    \draw[] (0,0) circle [radius=3cm];
    \foreach \angle [count=\xi] in \CircleIntervals
    {
        \draw[line width=1.5pt] (\angle:2.9cm) -- (\angle:3.1cm);
        \node[] at (\angle:3.5cm) {\xi};
    }
    \foreach \varA/\varB/\varD in \myInput {%
      \node[color=\varD] at (\varB:\foostate cm) {\Large{\varA}};
      \togglefoostate%
    }
    \end{tikzpicture}
\end{document}

Answer 2

evaluate您可以使用 Tikz提供的内置功能count。因此，我们从开始计数0，然后我们可以执行

evaluate=\xx as \mymod using {mod(\xx,2)},

结果将在哪里0,1,0,1,0,1,0,...。之后我们可以做

evaluate=\xx as \varC using int(2*(\mymod+1))

结果将是

int(2*(0+1)) == 2
int(2*(1+1)) == 4

代码

\documentclass[margin=10pt]{standalone}
\usepackage{tikz}

\def \CircleIntervals {0,90,...,270}
\def \myInput {
    foo/45/red,
    bar/135/green,
    baz/225/blue,
    qux/315/brown}

\begin{document}
\begin{tikzpicture}[line cap=rect, line width=3pt]
\draw[] (0,0) circle [radius=3cm];

\foreach \angle [count=\xi] in \CircleIntervals{
    \draw[line width=1.5pt] (\angle:2.9cm) -- (\angle:3.1cm);
    \node[] at (\angle:3.5cm) {\xi};
}

\foreach \varA/\varB/\varD [
    count=\xx starting from 0,
    evaluate=\xx as \mymod using {mod(\xx,2)},
    evaluate=\xx as \varC using int(2*(\mymod+1))
    ] in \myInput {%
    \node[color=\varD] at (\varB:\varC cm) {\Large{\varA}};
}

\end{tikzpicture}
\end{document}

Answer 3

在第二个循环中也使用计数，\yy如果计数为奇数则定义为 2，如果计数为偶数则定义为 4。

\documentclass[margin=5pt]{standalone}
\usepackage{tikz}

\newcommand\CircleIntervals {0,90,180,270}
\newcommand\myInput {
    foo/45/red,
    bar/135/green,
    baz/225/blue,
    qux/315/brown% <--- or a space would be seen
}

\begin{document}

\begin{tikzpicture}[line cap=rect, line width=3pt]
  \draw[] (0,0) circle [radius=3cm];
  \foreach \angle [count=\xi] in \CircleIntervals
   {
    \draw[line width=1.5pt] (\angle:2.9cm) -- (\angle:3.1cm);
    \node[] at (\angle:3.5cm) {\xi};
   }
  \foreach \varA/\varB/\varC [count=\y] in \myInput
   {
    \edef\yy{\ifodd\y\space 2\else 4\fi}
    \node[color=\varC] at (\varB:\yy cm) {\Large\varA};
   }
\end{tikzpicture}
\end{document}

奇怪的\space是用来终止的数字\ifodd。