\HeaderA{cdfGetFields}{Gets a subset of groups fields in a CDF structure}{cdfGetFields}
\keyword{programming}{cdfGetFields}
\keyword{internal}{cdfGetFields}
\begin{Description}\relax
Gets a subset of groups fields in a CDF structure.

This \code{\LinkA{function}{function}} is design to be used with \code{\LinkA{applyCdfGroups}{applyCdfGroups}}()
on an Affymetrix Mapping (SNP) CDF \code{\LinkA{list}{list}} structure.
\end{Description}
\begin{Usage}
\begin{verbatim}cdfGetFields(groups, fields, ...)\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{groups}] A \code{\LinkA{list}{list}} of groups.
\item[\code{fields}] A \code{\LinkA{character}{character}} \code{\LinkA{vector}{vector}} of names of fields to be returned.
\item[\code{...}] Not used.
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
Note that an error is \emph{not} generated for missing fields.
Instead the field is returned with value \code{\LinkA{NA}{NA}}.  The reason for this
is that it is much faster.
\end{Details}
\begin{Value}
Returns a \code{\LinkA{list}{list}} structure of groups.
\end{Value}
\begin{Author}\relax
Henrik Bengtsson (\url{http://www.braju.com/R/})
\end{Author}
\begin{SeeAlso}\relax
\code{\LinkA{applyCdfGroups}{applyCdfGroups}}().
\end{SeeAlso}

