Copy row duplicating data Xi times

explodeR.R

# Copy all rows in a dataframe according to their maximum value. 
# Copy all other integers an appropriate number of times, filling the last cell with 0.
#
# By StackOverflow user, CPak: https://stackoverflow.com/a/50930471/9962100
# 
# Example
# df <- data.frame(A1 = c(0,2,0,3), A2 = c(1,0,2,0), A3 = c(0,1,3,2))
# ans <- data.frame(A1 = c(0,2,2,0,0,0,3,3,3), A2 = c(1,0,0,2,2,0,0,0,0), A3 = c(0,1,0,3,3,3,2,2,0))
# library(magrittr)
# test <- do.call(rbind, lapply(seq_len(nrow(df)), function(x) explodeR(df[x, ]))) %>% as.data.frame
# all.equal(test, ans)

explodeR <- function(row) {
  M <- max(row)
  apply(row, 2, function(x) c(rep(x, times=x), rep(0, times=M-x)))
}