nicematrix matrix vs array - alignment specification

Question

I recently found the nicematrix package, and I am using it to for scripting.

Since my goal is to have a macro/environment which makes an augmented matrix (vertical line before the last column in my case), I was searching for a way to pass something like RRR|R as format string to pNiceMatrix.

Soon I figured out that this is not possible (right?) and found that the NiceArray environment would support this.

Since setting the parentheses is not a problem (I can specify this in my macro/environment declaration, thus later this is irrelevant),

I was wondering if I'd have any drawbacks by moving from pNiceMatrix to NiceArray?

Answer 1

For a matrix with (let's say) 3 columns, there is no difference between {pNiceMatrix} and {pNiceArray}{CCC}.

If you want a vertical rule, indeed, you need {pNiceArray} in order to have a explicit preamble.

\documentclass{article}

\usepackage{nicematrix}

\begin{document}

$\begin{pNiceMatrix}
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9 
\end{pNiceMatrix}
\qquad
\begin{pNiceArray}{CCC}
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9 
\end{pNiceArray}
\qquad
\begin{pNiceArray}{CC|C}
1 & 2 & 3 \\
4 & 5 & 6 \\
7 & 8 & 9 
\end{pNiceArray}$

\end{document}