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I am so new in R and want to write my own R cumsum() function. How can I create the function which takes in a length N vector of values to compute cumulative sums. Thanks

Phil
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Sienna Killingmoon
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    Are you asking how to write that specific function, or a function in general? If the former, what is your purpose of doing that instead of just using `cumsum()`? – Phil Jun 13 '21 at 14:47
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    What have you tried? Where are you getting stuck? Right now this isn't a specific programming question that's appropriate for Stack Overflow. If you are new to R, i'd recommend not trying to re-create optimized built in base functions. It's better to just use the existing function. If this is homework for some class or something, you could contact your instructor for guidance. – MrFlick Jun 13 '21 at 17:17
  • Following @MrFlick: if this is homework and you *don't* want to contact your instructor for whatever reason, you should show us how what you've tried to get started. See e.g. [this question on asking HW questions](https://meta.stackoverflow.com/questions/334822/how-do-i-ask-and-answer-homework-questions) – Ben Bolker Jun 13 '21 at 20:54

1 Answers1

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Here's a cumsum function using accumulate from the {purrr} package:

alt_cumsum <- function(x) {
  require(purrr)
  accumulate(x, `+`)
}

Example usage:

> alt_cumsum(1:5)
[1]  1  3  6 10 15
Rory S
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