Add asterisk after labels in enumerate

Question

I would like to add an asterisk after certain labels in the enumerate environment. So for example

\documentclass{article}
\begin{document}

\begin{enumerate}
    \item Kuttel
    \item* Daddeldu
\end{enumerate}

\end{document}

but without the space between 2. und *.

Answer 1

\documentclass[a4paper]{article}
\newenvironment{modenumerate}
  {\enumerate\setupmodenumerate}
  {\endenumerate}

\newif\ifmoditem
\newcommand{\setupmodenumerate}{%
  \global\moditemfalse
  \let\origmakelabel\makelabel
  \def\moditem##1{\global\moditemtrue\def\mesymbol{##1}\item}%
  \def\makelabel##1{%
    \origmakelabel{##1\ifmoditem\rlap{\mesymbol}\fi\enspace}%
    \global\moditemfalse}%
}

\begin{document}
\begin{modenumerate}
\item uno
\item due
\moditem{*} tre
\item\label{four} quattro
\moditem{*}[\hfill\ref{four}.] quattro
\end{modenumerate}
\end{document}

Answer 2

I have the following solution that puts stars before the labels:

\documentclass{article}

\begin{document}
\begin{enumerate}
\item A first item
  \bgroup
  \let\oldenum\labelenumi
  \renewcommand\labelenumi{*\oldenum}
  \item A starred item
  \egroup
\item A third item
  \bgroup
  \let\oldenum\labelenumi
  \renewcommand\labelenumi{*\oldenum}
  \item Another starred item
  \egroup
\end{enumerate}
\end{document}

Changing \renewcommand\labelenumi{*\oldenum} to \renewcommand\labelenumi{\oldenum *} messes up the alignment of the numbers.

I couldn't get this to work as a macro though.

Answer 3

One solution might be to tailor your labels like this:

\documentclass{article}
\begin{document}

\begin{enumerate}
    \item[1. ] Kuttel
    \item[2.*] Daddeldu
\end{enumerate}

\end{document}

Notice the extra space after the 1. in order to align 1 and 2 vertically.

Beware: this solution is pureley an aesthetic one for single levels enumerations. I don't know what will become of the nested items...

It is very simple but not scalable.