R/meltDT.R

In jchitpin/blistR:

meltDT <- function(DT){
    ## Determine last column before runs start
    minimumCol <- grep("ExactMass", colnames(DT))

    ## Melt data table; sample runs=variable
    DT <- melt(DT, measure.vars = c(colnames(DT)[(minimumCol+1):(length(DT))]))
    DT<- DT[!is.na(value)]
    DT[which(DT[, GeneralID == "STANDARD"]), GeneralID := "Standard"]
    num <- grep("Structural.ID.by.", colnames(DT))
    setnames(DT, num, "Validation")

    ## Split sample run names into relevant information
    DT <- DT[, c("run", "project", "matrix", "method") := tstrsplit(variable, ";_;")[1:4]]
    DT[, variable := NULL]

    return(DT)
}