[Tex/LaTex] Thick Lines on table

Question

I've seen the answer someone posted and I implemented it, I would like to keep this configuration as I already based my word using this answer.
Now, the question is, how can I make partial horizontal lines like what does \cline{-}.

Answer 1

In the following, we define a new version of \cline as \Cline where you can provide the required thickness.

\documentclass{article}

\makeatletter
\def\Cline#1#2{\@Cline#1#2\@nil}
\def\@Cline#1-#2#3\@nil{%
  \omit
  \@multicnt#1%
  \advance\@multispan\m@ne
  \ifnum\@multicnt=\@ne\@firstofone{&\omit}\fi
  \@multicnt#2%
  \advance\@multicnt-#1%
  \advance\@multispan\@ne
  \leaders\hrule\@height#3\hfill
  \cr}
\makeatother


\begin{document}

\begin{tabular}{ccc}
  \hline
  A & B & C\\\hline
  D & E & F\\
  \Cline{1-2}{5.0pt}
  G & H & I\\
  \Cline{1-2}{2.0pt}
  J & K & L\\
  \cline{1-2}
\end{tabular}

\end{document}

As can see, you are in control of the thickness when you use \Cline.

And the non-thick standard \cline is always there.

Should need all your \clines (and other lines) to be thick, change \arrayrulewidth to some value you wish.