# Example numbers with respect to chapters in tcolorbox title

I found this link which explains how to add index number to example in tcolorbox. However, I have been unable to modify it to include chapter reference numbering (e.g., Example 1.1, or 4.3, etc.). Any hints?

• Please provide some basic code in the form of a minimal example (or see here). You are more likely to attract a useful answer that way because you have shown that you are willing to help those who would help you. – jon Sep 6 '15 at 3:16

Updated 2015-08-29 to include a label, as requested by @Qasim.

Use tcolorbox's number freestyle option along with auto counter and number within=chapter, as in the following MWE. You can also add a label by using an optional (first) argument to \newtcolorbox (the second mandatory argument will be the title).

\documentclass{book}
\usepackage{tcolorbox}
\tcbuselibrary{skins,breakable}
\usepackage{lipsum}

\newtcolorbox[auto counter, number within=chapter, number freestyle={\noexpand\thechapter.\noexpand\arabic{\tcbcounter}}]{myexample}[2][]{%
enhanced,
breakable,
fonttitle=\bfseries,
title=Example~\thetcbcounter: #2,
#1
}

\begin{document}

\chapter{First chapter}

\begin{myexample}[label=exfirst]{First example}
\lipsum[4]
\end{myexample}

\begin{myexample}{Second example}
\lipsum[4]
\end{myexample}

\chapter{Second chapter}

\begin{myexample}[label=exthird]{Third example}
\lipsum[4]
\end{myexample}

I can now refer to example~\ref{exfirst} and example~\ref{exthird}.
\end{document}


Output:

If you would also like the title to be optional, you could use the following approach:

\documentclass{book}
\usepackage{etoolbox}
\usepackage{tcolorbox}
\tcbuselibrary{skins,breakable}
\usepackage{lipsum}

\tcbset{mytitle/.style={title={Example~\thetcbcounter\ifstrempty{#1}{}{: #1}}}}
\newtcolorbox[auto counter, number within=chapter, number freestyle={\noexpand\thechapter.\noexpand\arabic{\tcbcounter}}]{myexample}[1][]{%
enhanced,
breakable,
fonttitle=\bfseries,
mytitle={},
#1
}

\begin{document}

\chapter{First chapter}

\begin{myexample}[mytitle={First example}, label=exfirst]
\lipsum[4]
\end{myexample}

\begin{myexample}
\lipsum[4]
\end{myexample}

\chapter{Second chapter}

\begin{myexample}[mytitle={Third example}, label=exthird]
\lipsum[4]
\end{myexample}

I can now refer to example~\ref{exfirst} and example~\ref{exthird}.
\end{document}


Output:

• How do I refer to different examples in this case? For example, what should be Latex code for "as shown in Example 1.2"? – Qasim Chaudhari Aug 28 '15 at 4:41

You need to redefine the exa counter to achieve what you want:

\documentclass{book}
\usepackage[most]{tcolorbox}
\usepackage{lipsum}

\newcounter{exa}
\renewcommand\theexa{\thechapter.\arabic{exa}}
\tcbmaketheorem{Examples}{Example}{
breakable,
fonttitle=\bfseries,
}{exa}{ex}

\begin{document}
\chapter{Foo}