goodGenes: Filter genes with too many missing entries

Description Usage Arguments Details Value Author(s) See Also

View source: R/Functions.R

Description

This function checks data for missing entries and returns a list of genes that have non-zero variance and pass two criteria on maximum number of missing values: the fraction of missing values must be below a given threshold and the total number of missing samples must be below a given threshold.

Usage

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goodGenes(datExpr, 
          useSamples = NULL, 
          useGenes = NULL, 
          minFraction = 1/2, 
          minNSamples = ..minNSamples, 
          minNGenes = ..minNGenes, 
          tol = NULL,
          verbose = 1, indent = 0)

Arguments

datExpr

expression data. A data frame in which columns are genes and rows ar samples.

useSamples

optional specifications of which samples to use for the check. Should be a logical vector; samples whose entries are FALSE will be ignored for the missing value counts. Defaults to using all samples.

useGenes

optional specifications of genes for which to perform the check. Should be a logical vector; genes whose entries are FALSE will be ignored. Defaults to using all genes.

minFraction

minimum fraction of non-missing samples for a gene to be considered good.

minNSamples

minimum number of non-missing samples for a gene to be considered good.

minNGenes

minimum number of good genes for the data set to be considered fit for analysis. If the actual number of good genes falls below this threshold, an error will be issued.

tol

an optional 'small' number to compare the variance against. Defaults to the square of 1e-10 * max(abs(datExpr), na.rm = TRUE). The reason of comparing the variance to this number, rather than zero, is that the fast way of computing variance used by this function sometimes causes small numerical overflow errors which make variance of constant vectors slightly non-zero; comparing the variance to tol rather than zero prevents the retaining of such genes as 'good genes'.

verbose

integer level of verbosity. Zero means silent, higher values make the output progressively more and more verbose.

indent

indentation for diagnostic messages. Zero means no indentation, each unit adds two spaces.

Details

The constants ..minNSamples and ..minNGenes are both set to the value 4. For most data sets, the fraction of missing samples criterion will be much more stringent than the absolute number of missing samples criterion.

Value

A logical vector with one entry per gene that is TRUE if the gene is considered good and FALSE otherwise. Note that all genes excluded by useGenes are automatically assigned FALSE.

Author(s)

Peter Langfelder and Steve Horvath

See Also

goodSamples, goodSamplesGenes


WGCNA documentation built on Aug. 5, 2017, 5:05 p.m.