\HeaderA{applyCdfGroups}{Applies a function over the groups in a CDF structure}{applyCdfGroups}
\aliasA{applyCdfBlocks}{applyCdfGroups}{applyCdfBlocks}
\keyword{programming}{applyCdfGroups}
\begin{Description}\relax
Applies a function over the groups in a CDF structure.
\end{Description}
\begin{Usage}
\begin{verbatim}applyCdfGroups(cdf, fcn, ...)\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{cdf}] A CDF \code{\LinkA{list}{list}} structure.
\item[\code{fcn}] A \code{\LinkA{function}{function}} that takes a \code{\LinkA{list}{list}} structure of group elements
and returns an updated \code{\LinkA{list}{list}} of groups.
\item[\code{...}] Arguments passed to the \code{fcn} function.
\end{ldescription}
\end{Arguments}
\begin{Value}
Returns an updated CDF \code{\LinkA{list}{list}} structure.
\end{Value}
\begin{Section}{Pre-defined restructuring functions}
\Itemize{
\item[Generic:] \Itemize{
\item \code{\LinkA{cdfGetFields}{cdfGetFields}}() - Gets a subset of groups fields in a CDF
structure.
\item \code{\LinkA{cdfGetGroups}{cdfGetGroups}}() - Gets a subset of groups in a CDF structure.
\item \code{\LinkA{cdfOrderBy}{cdfOrderBy}}() - Orders the fields according to the value of
another field in the same CDF group.
\item \code{\LinkA{cdfOrderColumnsBy}{cdfOrderColumnsBy}}() - Orders the columns of fields according
to the values in a certain row of another field in the same CDF group.
}
\item[Designed for SNP arrays:] \Itemize{
\item \code{\LinkA{cdfAddBaseMmCounts}{cdfAddBaseMmCounts}}() - Adds the number of allele A and
allele B mismatching nucleotides of the probes in a CDF structure.
\item \code{\LinkA{cdfAddProbeOffsets}{cdfAddProbeOffsets}}() - Adds probe offsets to the groups in
a CDF structure.
\item \code{\LinkA{cdfGtypeCelToPQ}{cdfGtypeCelToPQ}}() - Function to immitate Affymetrix'
\code{gtype\_cel\_to\_pq} software.
\item \code{\LinkA{cdfMergeAlleles}{cdfMergeAlleles}}() - Function to join CDF allele A and
allele B groups strand by strand.
\item \code{\LinkA{cdfMergeStrands}{cdfMergeStrands}}() - Function to join CDF groups with the
same names.
}
}

We appreciate contributions.
\end{Section}
\begin{Author}\relax
Henrik Bengtsson (\url{http://www.braju.com/R/})
\end{Author}
\begin{Examples}
\begin{ExampleCode}
##############################################################
if (require("AffymetrixDataTestFiles")) {            # START #
##############################################################

cdfFile <- findCdf("Mapping10K_Xba131")

# Identify the unit index from the unit name
unitName <- "SNP_A-1509436"
unit <- which(readCdfUnitNames(cdfFile) == unitName)

# Read the CDF file
cdf0 <- readCdfUnits(cdfFile, units=unit, stratifyBy="pmmm", readType=FALSE, readDirection=FALSE)
cat("Default CDF structure:\n")
print(cdf0)

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Tabulate the information in each group
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cdf <- readCdfUnits(cdfFile, units=unit)
cdf <- applyCdfGroups(cdf, lapply, as.data.frame)
print(cdf)

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Infer the (true or the relative) offset for probe quartets.
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cdf <- applyCdfGroups(cdf0, cdfAddProbeOffsets)
cat("Probe offsets:\n")
print(cdf)

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Identify the number of nucleotides that mismatch the
# allele A and the allele B sequences, respectively.
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cdf <- applyCdfGroups(cdf, cdfAddBaseMmCounts)
cat("Allele A & B target sequence mismatch counts:\n")
print(cdf)


# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Combine the signals from  the sense and the anti-sense
# strands in a SNP CEL files.
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# First, join the strands in the CDF structure.
cdf <- applyCdfGroups(cdf, cdfMergeStrands)
cat("Joined CDF structure:\n")
print(cdf)

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Rearrange values of group fields into quartets.  This
# requires that the values are already arranged as PMs and MMs.
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cdf <- applyCdfGroups(cdf0, cdfMergeAlleles)
cat("Probe quartets:\n")
print(cdf)

# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
# Get the x and y cell locations (note, zero-based)
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
x <- unlist(applyCdfGroups(cdf, cdfGetFields, "x"), use.names=FALSE)
y <- unlist(applyCdfGroups(cdf, cdfGetFields, "y"), use.names=FALSE)

# Validate
ncol <- readCdfHeader(cdfFile)$cols
cells <- as.integer(y*ncol+x+1)
cells <- sort(cells)

cells0 <- readCdfCellIndices(cdfFile, units=unit)
cells0 <- unlist(cells0, use.names=FALSE)
cells0 <- sort(cells0)

stopifnot(identical(cells0, cells))

##############################################################
}                                                     # STOP #
##############################################################

\end{ExampleCode}
\end{Examples}

