Copy-pastable code using listings

Question

I'd like to have code in a PDF that someone can simply copy, paste, and use. Currently, \lstlisting is converting '-' to em dashes. Then when I paste the output into the Python interpreter or MATLAB, I get syntax errors. None of the solutions I've looked at on here seem to work.

myvar = 9
myvar = myvar - 2

The '-' ends up as '−' in the output.

I have the following settings

\lstset{breakatwhitespace,
language=MATLAB,
columns=fullflexible,
keepspaces,
breaklines,
tabsize=3, 
showstringspaces=false,
extendedchars=true,
basicstyle=\fontfamily{pcr}\selectfont\scriptsize,
keywordstyle=\color{orange},
upquote=true}

I am using \documentclass{beamer}

I've looked at

1. listings package changes hyphens to minus signs
2. less relevant since i'm focusing on code, not comments: Avoiding "minus sign" dash in listings commentstyle

Answer 1

You can use literate to change possible automated conversions. In this specific case, using literate={-}{-}1 substitutes - for - as-is:

\documentclass{beamer}

\usepackage{listings,textcomp}

\lstset{
  breakatwhitespace,
  language=MATLAB,
  columns=fullflexible,
  keepspaces,
  breaklines,
  tabsize=3, 
  showstringspaces=false,
  extendedchars=true,
  basicstyle=\fontfamily{pcr}\selectfont\scriptsize,
  keywordstyle=\color{orange},
  upquote=true,
  literate={-}{-}1}

\begin{document}

\begin{frame}[fragile]
\frametitle{A listing}

\begin{lstlisting}
myvar = 9
myvar = myvar - 2
\end{lstlisting}

\end{frame}

\end{document}