Possible to adjust character width?

Question

I'm using Beamer and lstlisting to put some code in a presentation.

The character spacing feels a bit too wide to my eye. Is it possible to reduce it? I've tried searching on this SE but can't seem to see anything obvious.

EDIT:

This seems trivial but:

\begin{frame}[fragile]
\frametitle{A frame}
\begin{lstlisting}
the letters are too far apart
\end{lstlisting}
\end{frame}

Answer 1

The default setting of listings is to place each character in a box in order to ensure vertical alignment emulating terminal output.

However, this may not be nice when the default font is proportionally spaced. There are two solutions (actually one):

\lstset{columns=fullflexible}

in the document preamble will typeset in normal character boxes. However, usually listings are typeset with a monospaced font, so

\lstset{columns=fullflexible,basicfamily=\ttfamily}

will do both settings.

The key-value pair can also be specified on a local basis:

\begin{lstlisting}[columns=fullflexible,basicfamily=\ttfamily]

will apply the settings only to that lstlisting environment.

The key keepspaces will also avoid merging two spaces into one.