Calculating cumulative sum for each row

Question

I am trying to calculate the cumulative sum for each row using the following code:

df <- data.frame(count=1:10)  for (loop in (1:nrow(df)))     {df[loop,"acc_sum"] <- sum(df[1:loop,"count"])} 

But I don't like the explicit loop here, how can I modify it?

Answer 1

You want cumsum()

df <- within(df, acc_sum <- cumsum(count))