Random shuffle itemize

Question

Is there an environment (or macro for itemize) that shuffles all items randomly each time the pdf is generated?

Answer 1

FWIW, ConTeXt supports this out of the box. Simply add the random key to \startitemize. (In ConTeXt, \startitemize[n] is equivalent to \begin{enumerate} of LaTeX).

\starttext
\startitemize[n,random]
  \startitem One \stopitem
  \startitem Two \stopitem
  \startitem Three \stopitem
  \startitem Four \stopitem
  \startitem Five \stopitem
  \startitem Six \stopitem
\stopitemize
\stoptext

which gives:

The random seed is stored in the tuc file so that you get the same output each time the file is compiled (otherwise, multiple compiles can lead to an infinite cycle and you may not get all the references correct). So you need to delete the tuc file to change the random seed, and hence get a different output.

Answer 2

As the usual implementation of \begin{list} \item ... \item ... \item ... \end{list} doesn't read or save the actual text of the items, some out-of-my-league hacking needs to be done to save then permute list items if you want the same interface.

I asked a similar question on the pgf-users mailing list several years ago. Here is Mark Wibrow's answer for randomizing a PGF list of the form declared by \pgfmathdeclarelist. I've dropped this snippet into my exam files ever since.

\documentclass{article} 
\usepackage{tikz} 

\begin{document} 

\makeatletter 
\def\pgfmathdeclarelist#1#2{% 
        \def\pgfmath@list@name{#1}% 
        \c@pgfmath@counta=0% 
        \pgfmath@declarelistlist#2{\pgfmath@stop}% 
}% 
\def\pgfmath@declarelistlist#1{% 
        \ifx#1\pgfmath@stop% 
                \expandafter\edef\csname pgfmath@list@\pgfmath@list@name 
@length\endcsname{\the\c@pgfmath@counta}% 
        \else% 
                \advance\c@pgfmath@counta by1\relax% 
                \pgfutil@namedef{pgfmath@list@\pgfmath@list@name @\the\c@pgfmath@counta}{#1}% 
                \expandafter\pgfmath@declarelistlist% 
        \fi% 
} 

\def\pgfmathgetlistitem#1#2#3{\expandafter\let\expandafter#1\expandafter=\csname 
pgfmath@list@#2@#3\endcsname} 

\def\pgfmathsetlistitem#1#2#3{% 
        \pgfutil@namedef{pgfmath@list@#1@#2}{#3}% 
} 

\def\pgfmathgetlistlength#1#2{% 
        \expandafter\let\expandafter#1\expandafter=\csname 
pgfmath@list@#2@length\endcsname% 
} 

\def\pgfmathknuthshuffle#1{% 
        \pgfmathgetlistlength\pgfmath@len{#1}% 
        \pgfmathloop% 
        \ifnum\pgfmathcounter>\pgfmath@len% 
        \else% 
                \pgfmathrandominteger\pgfmath@temp{1}{\pgfmath@len}% 
                \pgfmathgetlistitem\pgfmath@@temp{#1}{\pgfmathcounter}% 
                \pgfmathgetlistitem\pgfmath@@@temp{#1}{\pgfmath@temp}% 
                \def\pgfmath@marshal{\pgfmathsetlistitem{#1}}% 
                \expandafter\pgfmath@marshal\expandafter{\expandafter\pgfmath@temp\expandafter}\expandafter{\pgfmath@@temp}% 
                \expandafter\pgfmath@marshal\expandafter{\expandafter\pgfmathcounter\expandafter}\expandafter{\pgfmath@@@temp}% 
        \repeatpgfmathloop% 
} 

\makeatother 

\pgfmathdeclarelist{mylist}{{A}{B}{C}{D}{E}{F}{G}{H}{I}{J}{K}{L}{M}} 
\pgfmathgetlistlength{\l}{mylist} 

\begin{tikzpicture}[every node/.style={circle, draw}] 

\foreach \i in {1,...,\l}{ 
        \pgfmathgetlistitem{\x}{mylist}{\i} 
        \node at (0,-\i) (\x-1) {\x}; 
} 

\pgfmathknuthshuffle{mylist} 

\foreach \i in {1,...,\l}{ 
        \pgfmathgetlistitem{\x}{mylist}{\i} 
        \node at (7.5,-\i) (\x-2) {\x}; 
} 

\foreach \i in {1,...,\l}{ 
        \pgfmathgetlistitem{\x}{mylist}{\i} 
        \draw [->] (\x-1) -- (\x-2); 
} 

\end{tikzpicture} 
\end{document}