Cast a data.frame into a mutSignExposures-class object.
as.mutsign.exposures(x, samplesAsCols = TRUE)# S4 method for data.frame,logical
as.mutsign.exposures(x, samplesAsCols = TRUE)
a data.frame to be converted to a mutSignExposures-class object.
logical, are samples listed as columns in the input data.frame. If FALSE, samples are expected to be listed as rows in the input data.frame