From: Gabor Grothendieck <ggrothendieck_at_gmail.com>

Date: Sat, 26 Jul 2008 18:28:22 -0400

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat 26 Jul 2008 - 22:33:35 GMT

Date: Sat, 26 Jul 2008 18:28:22 -0400

Sorry, the last one should be:

ix <- match(B$DayOfYear, A$DayOfYear)

A[ix, "x"] <- A[ix, "x"] - B$x

Again we are assuming B's days are a subset of A's.

On Sat, Jul 26, 2008 at 6:08 PM, Gabor Grothendieck
<ggrothendieck_at_gmail.com> wrote:

> Here is a third solution.

*>
**> A[B$DayOfYear, "x"] <- A[B$DayOfYear, "x"] - B$x
**>
**> Its assumes B's days are a subset of A's but if that's not the case then
**> you would need to intersect them first: ?intersect
**>
**> On Sat, Jul 26, 2008 at 5:26 PM, <rkevinburton_at_charter.net> wrote:
**>> I have two vectos (list) that represent a years of data. Each "row" is represented by the day of year and the quantity that was sold for that day. I would like to form a new vector that is the difference between the two years of data. A sample of A (and similarly B) looks like:
**>>
**>>> A[1:5,]
**>> DayOfYear x
**>> 1 1 1429
**>> 2 2 3952
**>> 3 3 3049
**>> 4 4 2844
**>> 5 5 2219
**>>>
**>>
**>> D <- A - B
**>>
**>> This works just fine if A and B are both the same length. How is the best way to handle the situation where A and B are of different lengths? If the day of year exists in both vectors (lists) then I just want the coorespondng "row" in D to be the difference btween A and B values. If the "row" doesn't exist in either A or B then the difference should be treated as if the missing "row" was zero. Is this feasible?
**>>
**>> Thank you.
**>>
**>> Kevin
**>>
**>> ______________________________________________
**>> R-help_at_r-project.org mailing list
**>> **https://stat.ethz.ch/mailman/listinfo/r-help
**>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
**>> and provide commented, minimal, self-contained, reproducible code.
**>>
**>
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