Cross-reference entire enumerate list

Question

I would like to refer to all the items of an enumerate environment, by applying a label to the list. I tried this

\documentclass{article}[10pt]
\usepackage{amsmath, hyperref, enumerate}
\begin{document}
\setcounter{section}{1}
\begin{enumerate}\label{listref}
\item Mary
\item Had
\item A little
\item Lamb
\end{enumerate}
The poem \eqref{listref} is one of the best known childrens' rhymes.
\end{document}

but that did not produce the result required. I think labelling the first and the last items on the list is an option, but I was wondering if there is a smoother way of doing this.

Answer 1

For numbered environments which can be referenced, LaTeX provides theorem environments. They are not just theorems or definitions, you can use them more generally. You can

• use titles,
• attach the counter to a sectioning,
• share counters,
• and don't have to take care of defining an environment and managing a counter.

Further there are several packages for customizing these numbered environments, such as amsthm, ntheorem and thmtools. They provide predefined styles and ways for defining your own style.

Example:

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsthm}
\theoremstyle{definition}
\newtheorem{poem}{Poem}
\begin{document}
\begin{poem}\mbox{}\\[-\baselineskip]
  \begin{enumerate}\label{listref}
    \item Mary
    \item Had
    \item A little
    \item Lamb
    \end{enumerate}
\end{poem}
\noindent The poem \eqref{listref} is one of the best known childrens' rhymes.
\end{document}

For choosing a theorem package for customizing the format, have a look at: Theorem packages: which to use, which conflict?

Answer 2

I think you want something like this:

\newcounter{poemcnt}

\newenvironment{poem}%
  {\refstepcounter{poemcnt}\par Poem~\arabic{poemcnt}\begin{verse}}%
  {\end{verse}}

\begin{poem}
  \label{poemref}
  Mary\\
  Had\\
  A Little\\
  Lamb
\end{poem}

The poem~\ref{poemref} is one of the best known childrens' rhymes.

P.S. Mico asked for optional title. This is a little more involved :)

\newcounter{poemcnt}

\makeatletter
\newenvironment{poem}[1][]%
  {\refstepcounter{poemcnt}\par Poem~\arabic{poemcnt}%
    \def\@tempa{#1}\ifx\@tempa\@empty\else\space(#1)\fi
    \begin{verse}}%
  {\end{verse}}
\makeatother

\begin{poem}[Mary's Little Lamb]
  \label{poemref}
  Mary\\
  Had\\
  A Little\\
  Lamb
\end{poem}

Answer 3

In order to cross-reference the poem as a whole, you need to place it in an environment that is itself numbered (more specifically, an environment or grouping that comes with a counter of some sort). For instance, one can cross-reference items in an enumerated list by attaching labels to the individual items. Consider creating an enumerated list of poems as in the following example, which also uses the cleveref package and its ability to assign optional parameters to \label statements.

\documentclass{article}
\usepackage[colorlinks=true]{hyperref}
\usepackage{cleveref}
\crefname{poem}{poem}{poems}

\begin{document}
\section*{Nursery Rhymes}
\begin{enumerate}
\item Mary Had a Little Lamb \label[poem]{poem:mary}
   \begin{verse}
   Mary had a little lamb\\
   Its fleece was white as snow\\
   And everywhere that Mary went\\
   The lamb was sure to go.
   \end{verse}
\item Humpty Dumpty \label[poem]{poem:humpty}
   \begin{verse}
   Humpty Dumpty sat on a wall\\
   Humpty Dumpty had a great fall\\
   And all the king's horses and all the king's men\\
   Couldn't put Humpty together again.
   \end{verse}
\end{enumerate}

\Cref{poem:mary,poem:humpty} are among the best known nursery rhymes.
\end{document}

Answer 4

Bear in mind that a list doesn't display its "number" in-text by default even if one adds a (referable) counter to lists. Consider to put your list inside a figure environment and to provide a name for this figure with \caption -- this way, you may refer to the figure.

Note: \eqref{listref} produces nothing in your MWE because there's nothing to refer to in your document. Add \section{foo} immediately after \begin{document}, and your \eqref will (wrongly) refer to section 1.