# Different item symbols in a single list

I want this enumerate list to the following things:

1. Only the questions are labeled by (a), (b), (c). The answers should not be labeled at all.
2. These six lines should appear one by one. At first, only the first question is shown, followed by its answer after I press next page. Then the second question, then the second answer, ...

\documentclass[]{beamer}

\begin{document}

\begin{frame}
\frametitle{Example}
\begin{enumerate}[(a)]
\item<1-> Q: what is the answer to the first question?
\item<2-> A: The answer is A.
\item<3-> Q: what is the answer to the second question?
\item<4-> A: The answer is B.
\item<5-> Q: what is the answer to the second question?
\item<6-> A: The answer is C.
\end{enumerate}
\end{frame}

\end{document}


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One possibility is to create a custom empty item command:

\documentclass[]{beamer}

\begin{document}

\begin{frame}
\frametitle{Example}
\begin{enumerate}[<+->][(a)]    %new code
\item Q: what is the answer to the first question?
\item Q: what is the answer to the second question?
\item Q: what is the answer to the second question?
\end{enumerate}
\end{frame}

\end{document}


I also removed the individual overlay specifications and added an +- operator that affects the entire list.

As noted in the comments by @moewe, the code can be made more compact by adding the reused elements to the custom items definitions:

\documentclass[]{beamer}

\newcommand{\question}{\item Q:}   %new code
\begin{document}

\begin{frame}
\frametitle{Example}
\begin{enumerate}[<+->][(a)]
\question what is the answer to the first question?
\question what is the answer to the second question?
\question what is the answer to the second question?
\end{enumerate}
\end{frame}

\end{document}


The result is the same as as before. I'm not doing the same for the "what is the answer to..." parts because I suspect those are there just for the sake of the MWE

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This <+-> option is an abbreviated version of <1->, <2->, ..., right? –  Patrick Li Jan 1 '14 at 12:40
@PatrickLi kind of, see this answer for an explanation of the +- usage. –  dcmst Jan 1 '14 at 14:54
@moewe Yes, I agree. Extending your reasoning, you could eventually want to add to the answer item the repetitive part, like \newcommand{\answer}[1]{\item[] A: The answer is #1.} And then use it as \answer{A}. I'll update my answer. –  dcmst Jan 2 '14 at 10:45

Simply use [] to specify empty item labels. Definitely you can define your own macros as well for items like this.

\documentclass[]{beamer}

\begin{document}

\begin{frame}
\frametitle{Example}
\begin{enumerate}[(a)]
\item<1-> Q: what is the answer to the first question?
\item[]<2-> A: The answer is A.
\item<3-> Q: what is the answer to the second question?
\item[]<4-> A: The answer is B.
\item<5-> Q: what is the answer to the second question?
\item[]<6-> A: The answer is C.
\end{enumerate}
\end{frame}

\end{document}

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