Question

用Latex排版时 表格标题上面的这条线不知道是用什么命令画出来的

Answer 1

给你一个简单的例子：
\documentclass[a4paper,twocolumn]{article}
\newcommand{\mytoprule}{\rule{\linewidth}{0.4pt}\vspace{-2ex}}
\newcommand{\mybotrule}{\rule{\linewidth}{0.4pt}\vspace{-2.5ex}}
\usepackage{caption}
\captionsetup{format=plain,labelsep=period,font=bf,belowskip=5pt}
\begin{document}
I'll show you how to use this.\par
\begin{table}[!htb]
\centering
\mytoprule
\caption{This is a example about how to set the format of the caption of a tabular and draw a line above the caption}
\begin{tabular}{cc}
a & b \\
c & d \\
e & f \\
\end{tabular}
\mybotrule
\end{table}
And here is the text following the table.
\end{document}

追问

使用\mytoprule后表格标题上面的线是出来了（默认是黑色的，然后我把线设置成了彩色） 但是表格下面的字体也都变成了彩色。
\newcommand{\mytoprule}{\color{JPCCBlue}{\rule{\columnwidth}{1pt}}}
\newcommand{\mybotrule}{\color{JPCCBlue}{\rule{\columnwidth}{1pt}}}

追答

我已经在你新开的问题中回复了~在\color命令前后再多加一组花括号就行。