Fractional increment for enumerate

Question

I am looking to create a numbered list such that the numbers of the list items be incremented by fractional amounts as in 1.1, 1.2, 1.3... etc.

Can this be done by manipulating the enumerate counter?

Answer 1

Depending on the usage, enumitem allows to specify a label (and ref) option to enumerate. Here is a minimal example that steps some counter (mycount) at the start of every enumerate, and prints that counter in "fractional amounts":

\documentclass{article}
\usepackage{etoolbox}% http://ctan.org/pkg/etoolbox
\usepackage{enumitem}% http://ctan.org/pkg/enumitem
\newcounter{mycount} \renewcommand{\themycount}{\arabic{mycount}}%
\AtBeginEnvironment{enumerate}{\stepcounter{mycount}}% Increment mycount at \begin{enumerate}
\setlist[enumerate]{label=\themycount.\arabic*,ref=\themycount.\arabic*}
\begin{document}
\noindent Here is some text.
\begin{enumerate}
  \item An item
  \item Another item
  \item Yet another item
\end{enumerate}
Here is some more text.
\begin{enumerate}
  \item An item
  \item Another item
  \item Yet another item
\end{enumerate}
\end{document}

etoolbox provides the means to "tap into" the start of enumerate and update the mycount counter and every instance.

label refers to how the enumeration label will be typeset, while ref refers to how it will be referenced from within the document (if you're using \label and \ref). The settings for enumerate are made global (via \setlist[enumerate]{...}), although it could also be localized to a particular enumerate environment via an option argument:

\begin{enumerate}[label=.., ...]

If you're interested in labelling lists via some other counter (like section, or subsection, for instance), this is easily modifiable.

Answer 2

Here's another possible solution, which may appeal to people who like to use LaTeX's built-in functionality as much as possible.

I'm actually not perfectly sure if I've understood your question fully. Here's my interpretation of what you're looking for: you want to have separate first-level and second-level numbering systems, and the numbering of the second-level items should include the first level's counter as a "prefix". That way, if you have lots of second-level items, they'll get numbered as:

..., 1.8, 1.9, 1.10, 1.11, ... 

rather than as:

..., 1.8, 1.9, 2.0, 2.1, ...

Here's the MWE:

\documentclass{article}
\renewcommand\theenumii{\theenumi.\arabic{enumii}}
\renewcommand\labelenumii{\theenumii} % LaTeX's default: "(\theenumii)"
\makeatletter
\renewcommand\p@enumii{} % eliminate the default "prefix label", \theenumi
\makeatother
\begin{document}
\begin{enumerate}
\item First first-level item
  \begin{enumerate}
  \item A second-level item
  \item Another second-level item \label{enum:x}
  \end{enumerate}
\item Second first-level item \label{enum:y}
\end{enumerate}

\noindent
Here's a cross-reference to enumerated item \ref{enum:x},\\ 
and here's one to enumerated item \ref{enum:y}.
\end{document}