Brackets with a center bracket

Question

I have some data displayed in pairs. Currently, it appears like this, on one line:

(numbers; numbers; numbers)

However, I am looking for a better center divider. Here are some e.g.:

(numbers | numbers | numbers | numbers)
(numbers / numbers / numbers)

I am willing to change the outer brackets to any style, if necessary, to find a good match:

{numbers | numbers | numbers | numbers}
[numbers I numbers I numbers I numbers I numbers]

However, these all seem like good solutions. I cannot find any center divider that matches any of the outer dividers or that at least looks nice and visually separates the various parts.

What can I use?

Answer 1

You can use the \middle command which provides extensible delimiters for the middle of a set of outer delimiters (like \left and \right). For example:

\documentclass{article}
\begin{document}
\[
  \left\{\frac{a}{b} \middle] \frac{c}{d} \middle| \frac{e}{f} \middle( \frac{g}{h} \right\}
\]
\end{document}

In the above example, the outer \left and \right pairs match, while the inner \middle macros do not have to match in number nor in delimiter usage. The latter, actually, also holds for the \left and \right pair.