cumsum along row of data.frame with NA in R

Question

The hypothetical case is that there exist NA in a data.frame

> a <- c(1:5, NA, 7:10)
> b <- 1:10
> c <- 1:10
> 
> data <-         


        

Answer 1

Given your desired result (where you don't mind NA becoming 0), I guess the easiest thing is to first remove the NA values using is.na and then carry on as before.

data[ is.na(data) ] <- 0
data.frame(t(apply(data,1,cumsum)))