我有一个矩形，它有四个不同的顶点。我怎样才能只在其中三个顶点上放置圆圈？

Question

我对编码还很陌生，完全不知道自己在做什么。

\begin{tikzpicture}[
  mystyle/.style = {draw,shape=circle,fill=blue}
]
  \def\ngon{4}
  \node[regular polygon,regular polygon sides=\ngon,minimum size=5cm] (p) {};
  \foreach \x in {1,...,\ngon}{
    \node[mystyle] (p\x) at (p.corner \x){};
  }
  \foreach \x in {1,...,\numexpr\ngon-1\relax}{
    \foreach\y in {\x,...,\ngon}{ 
      \draw (p\x) -- (p\y);
    }
  }
\end{tikzpicture}

Answer 1

是那样的吗？

\documentclass{article}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}
 \draw(0,0)rectangle(1,1);
 \begin{scope}[radius=0.25cm]
 \draw(0,0)circle;
 \draw(0,1)circle;
 \draw(1,1)circle;
 \end{scope}
\end{tikzpicture}


\end{document}

Answer 2

欢迎使用 TeX.SE！我会使用\ifnum它。

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{shapes.geometric}
\begin{document}
\begin{tikzpicture}[
  mystyle/.style = {draw,shape=circle,fill=blue}
]
  \def\ngon{4}
  \node[regular polygon,regular polygon sides=\ngon,minimum size=5cm] (p) {};
  \foreach \x in {1,...,\ngon}{
    \ifnum\x=2
     \coordinate (p\x) at (p.corner \x);
    \else
     \node[mystyle] (p\x) at (p.corner \x){};
    \fi
  }
  \foreach \x in {1,...,\numexpr\ngon-1\relax}{
    \foreach\y in {\x,...,\ngon}{ 
      \draw (p\x) -- (p\y);
    }
  }
\end{tikzpicture}
\end{document}