Itemized table layout

Question

quick question: I copied this code:

\documentclass{article}
\usepackage{amsmath,amssymb,calc}
\def\horizlist#1#2#3{%
  \setcounter{enumi}{0}%
  #3%
  \flushleft
  \newlength\stringlength
  \setlength\stringlength{#2}
  \advance\stringlength by #1 \relax
  \def\item{\hfil\egroup\penalty50 \hfill
  \refstepcounter{enumi}%
  \leavevmode\hbox to \stringlength \bgroup\space(\theenumi)\space}
  \leavevmode\bgroup\hskip 0pt plus -1fill }

\def\endhorizlist{\hfil\egroup\endflushleft}

\begin{document}
\begin{enumerate}
\item blah
    \begin{horizlist}{2cm}{\widthof{null}}{\renewcommand\theenumi{\alph{enumi}}}
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \end{horizlist}
\end{enumerate}
\end{document}

It does what it should do, the only problem being that the last item appears on the right, not adjoint to its predecessor on the left. How can i fix this? To illuminate the problem:

The output is like this:

I want this:

Any Help?

Answer 1

You'll need to keep track of the current column. I find it easier (and also more flexible) to do the whole thing by defining the horizlist environment as a tabular. This way you can not only use \item instead of &/\\, but also specify the alignment as desired (the 2nd arg of the horizlist env).

\documentclass{article}
\usepackage{calc}

\newcount\horizlistcount
\newenvironment{horizlist}[2]{%
  \setcounter{enumi}{0}%
  \renewcommand\theenumi{\alph{enumi}}%
  \def\nextsep{}%
  \global\horizlistcount=#1
  \def\item{%
    \nextsep
    \refstepcounter{enumi}(\theenumi)
    \ifnum\horizlistcount=0 \global\horizlistcount=#1 \fi
    \global\advance\horizlistcount-1
    \ifnum\horizlistcount=0 \def\nextsep{\\}\else\def\nextsep{&}\fi
  }%
  \begin{tabular}[t]{*{#1}{#2}}
}{%
  \end{tabular}
}

\begin{document}
\begin{enumerate}
\item blah
    \begin{horizlist}{4}{p{\widthof{null}+2cm}}
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \end{horizlist}
\end{enumerate}
\end{document}

(To get into a new line before the embedded table, just say \\ in front of it, or include it into the definition.)

Answer 2

Not fully automated, but does what you need. We introduce a command \noitem which inserts "phantom item". The non-automated thing is that we do not know in advance how many \noitems should be there.

\documentclass{article}
\usepackage{amsmath,amssymb,calc}
\def\horizlist#1#2#3{%
  \setcounter{enumi}{0}%
  #3%
  \flushleft
  \newlength\stringlength
  \setlength\stringlength{#2}
  \advance\stringlength by #1 \relax
  \def\item{\hfil\egroup\penalty50 \hfill
  \refstepcounter{enumi}%
  \leavevmode\hbox to \stringlength \bgroup\space(\theenumi)\space}
  \def\noitem{\hfil\egroup\penalty50 \hfill
  \leavevmode\hbox to \stringlength \bgroup}
  \leavevmode\bgroup\hskip 0pt plus -1fill }

\def\endhorizlist{\hfil\egroup\endflushleft}

\begin{document}
\begin{enumerate}
\item blah
    \begin{horizlist}{2cm}{\widthof{null}}{\renewcommand\theenumi{\alph{enumi}}}
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \item null
    \noitem\noitem
    \end{horizlist}
\end{enumerate}
\end{document}