在实数行上添加带有一些文本的双箭头

Question

问：见附图，我该如何实现？我想在实线的两侧画箭头，并在箭头里面画一些文字。

梅威瑟：

\documentclass[12pt]{article}
\usepackage[bindingoffset=0.2in,left=0.5in,right=0.5in,top=0.5in,bottom=0.5in,footskip=.25in]{geometry}
\usepackage[centertags]{amsmath}
\usepackage{latexsym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{newlfont}
\usepackage{enumerate}
\usepackage{makeidx}
\usepackage{tikz}
\usetikzlibrary{arrows.meta}
\usepackage{xparse}
\usetikzlibrary{backgrounds,intersections}
\begin{document}    
    \begin{tikzpicture}[xscale=1.5]
        \draw[thick,latex-latex] (-5,0) -- (6,0)node[right]{};
        \foreach \x in {-4,-3,-2,-1,0,1,2,3,4}{
            \node[fill,circle,inner sep=1.20pt,label=below:$\x$] at (\x,0) {};
        };
    \end{tikzpicture}
\end{document}

Answer 1

这是通过改变节点的形状来实现的一种方法。请参阅代码中的注释。请参阅 tikzmanual 中的第 71.5 章和第 17.2.3 章。

\documentclass[12pt]{article}
\usepackage[bindingoffset=0.2in,left=0.5in,right=0.5in,top=0.5in,bottom=0.5in,footskip=.25in]{geometry}
% ~~~ commented out all that's not needed here ~~~~~~~~~
%\usepackage[centertags]{amsmath}
%\usepackage{latexsym}
%\usepackage{amsfonts}
%\usepackage{amssymb}
%\usepackage{amsthm}
%\usepackage{newlfont}
%\usepackage{enumerate}
%\usepackage{makeidx}
\usepackage{tikz}
\usetikzlibrary{arrows.meta}
%\usepackage{xparse}
%\usetikzlibrary{backgrounds,intersections}

\usetikzlibrary{shapes.arrows}

\begin{document}    
    \begin{tikzpicture}[
        xscale=1.5,
        dots/.style={fill,circle,inner sep=1.20pt},
    ]
        \draw[thick,latex-latex] (-5,0) -- (6,0)node[right]{};
%        \foreach \x in {-4,-3,-2,-1,0,1,2,3,4}{% can be shortened
        \foreach \x in {-4,-3,...,4}{
            \node[dots,label=below:$\x$] at (\x,0) {};
        };
        
        % ~~~ arrows ~~~~~~~~~~~~~~
        \node[  single arrow,       % node shaped like an arrow
                anchor=west,        % i.e. the postion below
                fill=green!40,draw=blue
            ] 
                at (0.3,1) {Some text};
                
        \node[  single arrow,
                anchor=east,
                fill=red!40,draw=purple,
                shape border rotate=180,    % rotates shape, not text
              ] 
                at (-0.3,1) {Some more text};
    \end{tikzpicture}
\end{document}

附言对于彩色点，只需拆分循环并执行以下操作：

        \foreach \x in {-4,-3,-2,-1}{
            \node[dots,,fill=red,label=below:$\x$] at (\x,0) {};
        };
        \foreach \x in {1,2,3,4}{
            \node[dots,fill=green,label=below:$\x$] at (\x,0) {};
        };