Sum list of numbers until threshold

Question

I have a list of integers that I want to sum until a threshold value is met, and then be able to access the index at which the threshold is reached.

Something like:

summing <- function(i){
sum = sum + list[i]
index = i
while(sum < thresholdValue){
summing(i++)
}}

However, I'm not well versed on writing functions in R so not 100% sure on how this should be done.

`++` is not a thing in R, and you need a `return` statement. Otherwise, your code seems fine, as an exercise. — Frank, Dec 11 '15 at 13:26

score 8 · Accepted Answer · answered Dec 11 '15 at 13:27

8

Try this example:

#data
x <- 1:10 

#set threshold
thresholdValue <- 13

#index
ix <- length(which(cumsum(x) <= thresholdValue))
# 4

#sum
sum(x[1:ix])
#[1] 10

answered Dec 11 '15 at 13:27

zx8754

2

short: `w <- which(cumsum(x) <= thresholdValue); sum(x[w])` – jogo Dec 11 '15 at 13:36

1 Answers1