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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/helper.R
\name{collapseReplicates}
\alias{collapseReplicates}
\title{Collapse technical replicates in a RangedSummarizedExperiment or DESeqDataSet}
\usage{
collapseReplicates(object, groupby, run, renameCols = TRUE)
}
\arguments{
\item{object}{A \code{RangedSummarizedExperiment} or \code{DESeqDataSet}}
\item{groupby}{a grouping factor, as long as the columns of object}
\item{run}{optional, the names of each unique column in object. if provided,
a new column \code{runsCollapsed} will be added to the \code{colData}
which pastes together the names of \code{run}}
\item{renameCols}{whether to rename the columns of the returned object
using the levels of the grouping factor}
}
\value{
the \code{object} with as many columns as levels in \code{groupby}.
This object has \code{"counts"} data which is summed from the various
columns which are grouped together, and the \code{colData} is subset using
the first column for each group in \code{groupby}.
Other assays are dropped, as it is not unambiguous the correct
form of combination, and a warning is printed if they are present, so
the user is aware they should take care of such assays manually.
}
\description{
Collapses the columns in \code{object} by summing within levels
of a grouping factor \code{groupby}. The purpose of this function
is to sum up read counts from technical replicates to create an object
with a single column of read counts for each sample.
This function will issue a warning if there are other assays other than
\code{"counts"}, see details below in 'Value'.
}
\details{
Note: by "technical replicates", we mean multiple sequencing runs of the same
library, in constrast to "biological replicates" in which multiple
libraries are prepared from separate biological units.
Optionally renames the columns of returned object with the levels of the
grouping factor.
Note: this function is written very simply and
can be easily altered to produce other behavior by examining the source code.
}
\examples{
dds <- makeExampleDESeqDataSet(m=12)
# make data with two technical replicates for three samples
dds$sample <- factor(sample(paste0("sample",rep(1:9, c(2,1,1,2,1,1,2,1,1)))))
dds$run <- paste0("run",1:12)
ddsColl <- collapseReplicates(dds, dds$sample, dds$run)
# examine the colData and column names of the collapsed data
colData(ddsColl)
colnames(ddsColl)
# check that the sum of the counts for "sample1" is the same
# as the counts in the "sample1" column in ddsColl
matchFirstLevel <- dds$sample == levels(dds$sample)[1]
stopifnot(all(rowSums(counts(dds[,matchFirstLevel])) == counts(ddsColl[,1])))
}
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