\HeaderA{null2na}{Turns null or NA into character "NA"}{null2na}
\keyword{models}{null2na}
\begin{Description}\relax
The functions turns NULL or NA into character "NA"
\end{Description}
\begin{Usage}
\begin{verbatim}
null2na(x)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] A vector 
\end{ldescription}
\end{Arguments}
\begin{Value}
Either the original vector (if not NULL or logical NA) or character NA
\end{Value}
\begin{Author}\relax
Tony Chiang <tchiang@ebi.ac.uk>
\end{Author}
\begin{Examples}
\begin{ExampleCode}
null2na(NA)
null2na(NULL)
\end{ExampleCode}
\end{Examples}

