Internal delimiters for matrix and array

Question

I would like to customize the array environment in such a way that I can write arrays with dashed delimiters that are internal to the arrays as in the figure below.

Question. How do I place the vertical and horizontal delimiters on the inside of the arrays? Is it possible to have control over the customization of the delimiters? Like can I control the delimiters so that they are dashed or continuous or colored?

Thanks in advance.

My attempt. The best I got was using the code below.

    \begin{center}
    \left[\begin{array}{c|c|c}
    \underline{\displaystyle{A}_{\vspace{5mm}}} 
    & 
    \underline{\displaystyle{B}_{\vspace{5mm}}} 
    & 
    \underline{\displaystyle{E}_{\vspace{5mm}}} 
    \\ 
    \underline{\displaystyle{C}_{\vspace{5mm}}}
    & 
    \underline{\displaystyle{D}_{\vspace{5mm}}}
    & 
    \underline{\displaystyle{F}_{\vspace{5mm}}}
    \\
    \underline{\displaystyle{G}_{\vspace{5mm}}}
    &
    \underline{\displaystyle{H}_{\vspace{5mm}}}
    & 
    \underline{\displaystyle{L}_{\vspace{5mm}}}
    \end{array}\right]
    \end{center}

And the result was somewhat unsatisfactory as can be seen in the figure below.

Does this solve your problem? https://tex.stackexchange.com/a/20141 — antshar, May 22 '20 at 17:12
@antshar Yes+1. Answer my question. It helped a lot. But is there an alternative without using the "arydshln" package? — MathOverview, May 22 '20 at 17:16
@MathOverview: With nicematrix you can do that with dotted lines. And you can use both nicematrix and arydshln. — F. Pantigny, May 22 '20 at 17:22

score 2 · Answer 1 · answered Jul 13 '20 at 22:19

As from suggestion of the creator F. Pantigny of nicematrix package, I add the differents output considering also the comments.

\documentclass[a4paper,12pt]{article}
\usepackage{amssymb}
\usepackage{nicematrix}
\usepackage{arydshln}
\begin{document}
\setlength{\extrarowheight}{1mm}
\renewcommand{\arraystretch}{1}
[\left[,\begin{NiceArray}{c:c:c}
A & B & C  \
\hdashline
D & E & F \
\hdashline
G & H & O
\end{NiceArray},\right]
]
[\left[,\begin{NiceArray}{c:c}
A & B   \
\hdashline
D & E  \
\end{NiceArray},\right]
]
[\left[,\begin{NiceArray}{c}
A  \
\hdashline
D   \
\end{NiceArray},\right]
]
[\left[\begin{NiceArray}{c:c}
A  & V\
\end{NiceArray}\right]
]
\end{document}

Internal delimiters for matrix and array

1 Answers1