实心圆圈

Question

我有一堆直线，我只想在任意位置（比如在端点）放置大圆点，颜色连续（红、蓝、红、蓝）。我尝试过，但无法从网上获得任何帮助。

\documentclass[border=2mm]{standalone}

\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
    \begin{tikzpicture}

     \draw (0,0) -- (0,4);
     \draw (0.3,0) -- (0.3,4);
     \draw (0.8,0) -- (0.8,4);
     \draw (1.1,0) -- (1.1,4);
     \draw (1.6,0) -- (1.6,4);
     \draw (1.9,0) -- (1.9,4);
     \node[anchor=west] at (axis cs:18.5,-0.019){\textbullet};

    \end{tikzpicture}
\end{document}

这是我的失败尝试

Answer 1

实心圆圈

该示例将端点命名1bot为和6bot，1top以便6top更容易地独立于实际坐标对它们进行着色。

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
  \begin{tikzpicture}
    \draw
      \foreach[count=\i] \x in {0, 0.3, 0.8, 1.1, 1.6, 1.9} {
        (\x, 0) coordinate (\i bot) -- (\x, 4) coordinate (\i top)
      }
    ;
    \fill[red, radius=2pt]
      \foreach \i in {1, ..., 6} {
        (\i bot) circle[]
      }
    ;
    \fill[blue, radius=2pt]
      \foreach \i in {1, ..., 6} {
        (\i top) circle[]
      }
    ;
  \end{tikzpicture}
\end{document}

地块标记

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
  \begin{tikzpicture}
    \draw
      \foreach[count=\i] \x in {0, 0.3, 0.8, 1.1, 1.6, 1.9} {
        (\x, 0) coordinate (\i bot) -- (\x, 4) coordinate (\i top)
      }
    ;
    \path plot[mark=*, mark options=red] coordinates {
      (1bot) (2top) (3bot) (4top) (5bot) (6top)
    };
    \path plot[mark=*, mark options=blue] coordinates {
      (1top) (2bot) (3top) (4bot) (5top) (6bot)
    };
  \end{tikzpicture}
\end{document}

此外，线条还可以着色（根据评论)：

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
  \begin{tikzpicture}
    \draw[red]
      \foreach[count=\i] \x in {0, 0.8, 1.6} {
        (\x, 0) coordinate (r\i bot) -- (\x, 4) coordinate (r\i top)
      }
    ;
    \draw[blue]
      \foreach[count=\i] \x in {0.3, 1.1, 1.9} {
        (\x, 0) coordinate (b\i bot) -- (\x, 4) coordinate (b\i top)
      }
    ;
    \path plot[mark=*, mark options=red] coordinates {
      (r1bot) (b1top) (r2bot) (b2top) (r3bot) (b3top)
    };
    \path plot[mark=*, mark options=blue] coordinates {
      (r1top) (b1bot) (r2top) (b2bot) (r3top) (b3bot)
    };
  \end{tikzpicture}
\end{document}