lokheart lokheart - 7 days ago 6
R Question

calculating cumulative sum for each row in R

I am trying to calculate the cumulative sum for each row in R 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? Thanks.

Answer

You want cumsum()

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