[R] Is there a funct to sum differences?

[Jeff Newmiller]

Could you make your example reproducible? That is, include some sample input and output. You talk about a column of numbers and then you seem to work with named lists and I can't reconcile your words with the code I see. 
-- 
Sent from my phone. Please excuse my brevity.

On December 23, 2016 3:40:18 PM PST, arthur brogard via R-help <r-help at r-project.org> wrote:
>I've been looking but I can't find a function to sum difference.
>
>I have this code:
>
> 
>rates$thisone <- c(diff(rates$Int), NA)
>rates$nextone <- c(diff(rates$Int, lag=2), NA, NA)
>rates$lastone <- (rates$thisone + rates$nextone)
>
>
>It is looking down one long column of numbers.
>
>It sums the difference between the first two and then between the first
>and third and so on.
>
>Can it be made to automatically sum the difference between the first
>and subsequent to the end of a list?
>
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