Write vectors of unequal sizes to excel

sigxcel.R

library(openxlsx)
library(magrittr)
library(plyr)

wb.init <- function() {
    wb <- openxlsx::createWorkbook()
    return(wb)
}

wb.add.sheet <- function(wb, sheet="1", signatures) {
    df <- lapply(names(signatures), function(x) {
             df <- data.frame(x=signatures[[x]])
             colnames(df) <- c(x)
             return(df)
          }) %>%
          do.call(plyr::rbind.fill, .) %>%
          apply(2, sort, na.last=TRUE) %>%
          data.frame()
    openxlsx::addWorksheet(wb, sheetName=sheet)
    openxlsx::writeData(wb, sheet=sheet, x=df, colNames=TRUE, rowNames=FALSE)
}

# Signatures of unequal length
signature.alpha <- list("A"=c("G1", "G2", "G3", "G4", "G5"),
                        "B"=c("G1", "G2", "G3"),
                        "C"=c("G1"))

# Write to excel
wb <- wb.init()
wb.add.sheet(wb, sheet="Alpha", signature.alpha)
openxlsx::saveWorkbook(wb, file="example.xlsx", overwrite=FALSE)