# Beamer - Frame numbering in alphabetic format

I have redefined the footline of appendix frames in beamer. Now the frames after appendix show framenumber from one. Following is the code used:

\documentclass[•]{beamer}
\def\insertpresentationendframe{\inserttotalframenumber}
\makeatletter
\g@addto@macro{\appendix}{\immediate\write\@auxout{\string\@writefile{nav}{\noexpand\headcommand{\noexpand\def\noexpand\insertpresentationendframe{\the\c@framenumber}}}}}
\makeatother

\begin{document}
\begin{frame}
The frame before appendix\\
Frame number = 1
\end{frame}

\appendix
\setbeamertemplate{footline}{\number\numexpr\insertframenumber-\insertpresentationendframe}
\begin{frame}
First frame of appendix\\
Actual frame number=2\\
What is now printed = 1
\end{frame}
\end{document}


My question is, how I can print the frame numbers of the footline in alphabetic mode ? I tried this:

\setbeamertemplate{footline}{\alph{\number\numexpr\insertframenumber-\insertpresentationendframe}}


but the code did not compile. Does anybody know how to fix this ? Please note that I don't want to redefine the frame numbering (as it will cause issues with my custom theme), but to print a different frame number (which is frame number - number of presentation end frame).

Thanks in advance.

## 1 Answer

I hope that I interpret your question correctly.

\documentclass[¥]{beamer}
\def\insertpresentationendframe{\inserttotalframenumber}
\newcounter{fakepage}
\makeatletter
\g@addto@macro{\appendix}{\immediate\write\@auxout{\string\@writefile{nav}{\noexpand\headcommand{\noexpand\def\noexpand\insertpresentationendframe{\the\c@framenumber}}}}}
\makeatother

\begin{document}
\begin{frame}
The frame before appendix\\
Frame number = 1
\end{frame}

\appendix
\setbeamertemplate{footline}{\setcounter{fakepage}{\number\numexpr\insertframenumber-\insertpresentationendframe}
\alph{fakepage}}
\begin{frame}
First frame of appendix\\
Actual frame number=2\\
What is now printed = 1
\end{frame}
\end{document}

• Thank you very much marmot, my earlier attempts by defining counters failed because I defined setcounter outside \setbeamertemplate{footline}. Thanks again ! Jan 18, 2018 at 19:42