# [R] Is there a funct to sum differences?

arthur brogard abrogard at yahoo.com
Sat Dec 24 06:29:21 CET 2016

```Yes, sorry about that.  I keep making mistakes I shouldn't make.

You can ignore the finalone. I have been doing other work on this and it comes from there. I took the example from the R screen after it had run one of these other things that created the finalone.

I guess I was thinking just seeing the data mentioned in the code was be enough.

I don't want a function to do the division and multiplication.

It's a function that will ".. automatically sum the difference between the first

and subsequent to the end of a list? "  that I am looking for.

I will try to explain, I know I often don't make myself clear:

I'm using this diff() function.

This 'diff()' function finds the difference between two adjoining entries and it applies itself to the whole list so that in an instant I can have a list of differences between any two adjoining.

Then I can have a list of differences between any two with any specified gap - 'lag' it is called.
Using the same function.

Now I have them and do that.  Then I add them together to find the 'lastone' which is the total difference for the period.

Now here's the point:  that covers a period of two timespans, months, they are.

if I want to cover a span of 24 months, say, then I would have to write this diff() function 24 times.

what I'm doing is finding the difference between the starting point and every other point and then adding them all together.  bit like finding the area beneath the curve maybe.

And that's what I want to do.

:)

----- Original Message -----
From: Jeff Newmiller <jdnewmil at dcn.davis.ca.us>
To: arthur brogard <abrogard at yahoo.com>
Cc: r-help at r-project.org
Sent: Saturday, 24 December 2016, 15:34
Subject: Re: [R] Is there a funct to sum differences?

You need to "reply all" so other people can help as well, and others can

I am still puzzled by how you expect to compute "finalone". If you had
supplied numbers other than all 5's it might have been easier to figure
out what is going on.

What is your purpose in performing this calculation?

#### reproducible code
"Date          Int
Jan-1959        5
Feb-1959        5
Mar-1959        5
Apr-1959        5
May-1959        5
Jun-1959        5
Jul-1959        5
Aug-1959        5
Sep-1959        5
Oct-1959        5
Nov-1959        5
", header = TRUE, colClasses = c( "character", "numeric" ) )

rates\$thisone <- c(diff(rates\$Int), NA)
rates\$nextone <- c(diff(rates\$Int, lag=2), NA, NA)
rates\$lastone <- (rates\$thisone + rates\$nextone)/6.5*1000
# I doubt there is a ready-built function that knows you want to
# divide by 6.5 or multiply by 1000

# form a vector from positions 2:11 and append NA)
rates\$experiment1 <- rates\$Int + c( rates\$Int[ -1 ], NA )
# numbers that are not all the same
rates\$Int2 <- (1:11)^2
rates\$experiment2 <- rates\$Int2 + c( rates\$Int2[ -1 ], NA )

# dput(rates)
result <- structure(list(Date = c("Jan-1959", "Feb-1959", "Mar-1959",
"Apr-1959",
"May-1959", "Jun-1959", "Jul-1959", "Aug-1959", "Sep-1959", "Oct-1959",
"Nov-1959"), Int = c(5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5), thisone = c(0,
0, 0, 0, 0, 0, 0, 0, 0, 0, NA), nextone = c(0, 0, 0, 0, 0, 0,
0, 0, 0, NA, NA), lastone = c(0, 0, 0, 0, 0, 0, 0, 0, 0, NA,
NA), Int2 = c(1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121), experiment1 =
c(10,
10, 10, 10, 10, 10, 10, 10, 10, 10, NA), experiment2 = c(5, 13,
25, 41, 61, 85, 113, 145, 181, 221, NA)), .Names = c("Date",
"Int", "thisone", "nextone", "lastone", "Int2", "experiment1",
"experiment2"), row.names = c(NA, -11L), class = "data.frame")

On Sat, 24 Dec 2016, arthur brogard wrote:

>
>
> Yes, sure, thanks for your interest.  I apologise for not submitting in the correct manner.  I'll learn (I hope).
>
> Here's the source - a spreadsheet with just two columns, date and 'Int'.
>
>
> Date    Int
> Jan-1959    5
> Feb-1959    5
> Mar-1959    5
> Apr-1959    5
> May-1959    5
> Jun-1959    5
> Jul-1959    5
> Aug-1959    5
> Sep-1959    5
> Oct-1959    5
> Nov-1959    5
>
>
> After processing it becomes this:
>
>
>> rates
> Date   Int thisone nextone     lastone finalone
> 1   1959-01-01  5.00    0.00    0.00    0.000000       10
> 2   1959-02-01  5.00    0.00    0.00    0.000000       10
> 3   1959-03-01  5.00    0.00    0.00    0.000000       10
> 4   1959-04-01  5.00    0.00    0.00    0.000000       10
> 5   1959-05-01  5.00    0.00    0.00    0.000000       10
> 6   1959-06-01  5.00    0.00    0.00    0.000000       10
>
> The one long column I'm referring to is the 'Int' column which R has imported.
>
> The actual code is:
>
>
>
> sapply(rates,class)
>
> rates\$Date <- strptime(paste0("1-", rates\$Date), format="%d-%b-%Y", tz="UTC")
>
>
> rates\$thisone <- c(diff(rates\$Int), NA)
> rates\$nextone <- c(diff(rates\$Int, lag=2), NA, NA)
> rates\$lastone <- (rates\$thisone + rates\$nextone)/6.5*1000
>
>
> rates
>
>
>
> ab
>
>
>
> ----- Original Message -----
> From: Jeff Newmiller <jdnewmil at dcn.davis.ca.us>
> To: arthur brogard <abrogard at yahoo.com>; arthur brogard via R-help <r-help at r-project.org>; "r-help at r-project.org" <r-help at r-project.org>
> Sent: Saturday, 24 December 2016, 13:25
> Subject: Re: [R] Is there a funct to sum differences?
>
> 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?
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
>

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