How can I use monospaced font inside a matrix (or tabular etc)?

Question

I would like to display a matrix with characters using monospaced font (as in \tt and \mathtt), but I haven't found an easy way to do it. Something like this:

\begin{center}{\tt\left(
\begin{tabular}{cccc}
  A & B & C & D\\
  E & F & G & H\\
  I & J & K & L
\end{tabular}\right)}.
\end{center}

But this won't work, because I used \left( and \right) outside math environment.

\[
{\mathtt
\begin{pmatrix}
  A & B & C & D\\
  E & F & G & H\\
  I & J & K & L
\end{pmatrix}
}
\]

This one won't work either:

! Missing \endcsname inserted.

I know I can do this by using {\mathtt A} & {\mathtt B}, and so on, for each matrix element, but that would be really a pain (I have more matrices).

Is there a simple way to do this?

Answer 1

I don't think it's a good idea to use the tabular environment inside a math group; instead, use the (very similar) array environment.

The following example code uses the newcolumntype command of the array package to create the t column type, which typesets its contents in monospaced font.

\documentclass{article}
\usepackage{array}
\newcolumntype{t}{>{\tt}c}
\begin{document}
\[ \left( \begin{array}{tttt}
  A & B & C & D\\
  E & F & G & H\\
  I & J & K & L
\end{array} \right) \]
\end{document}

Instead of \left( and \right) parentheses around the matrix, you could also use \left[ and \right] for square brackets, \left\{ and \right\} for curly braces, and \left\lvert and \right\rvert for straight lines, to name a few possibilities.

Answer 2

\usepackage{array}
\newcolumntype{t}{>{\ttfamily}c}

\[
\left(\begin{tabular}{tttt}
  A & B & C & D\\
  E & F & G & H\\
  I & J & K & L
\end{tabular}\right)
\]

A tabular is quite good also in math mode. With \newcolumntype{t}{>{\ttfamily}c} you define a column made by centered cells typeset in typewriter type.