[R] Data length mismatch.

[Gabor Grothendieck]

Look at merge.zoo

> library(zoo)
> dput(A)
structure(list(DayOfYear = 1:5, x = c(1429L, 3952L, 3049L, 2844L,
2219L)), .Names = c("DayOfYear", "x"), class = "data.frame", row.names = c("1",
"2", "3", "4", "5"))
> B <- A[c(2,4),]
> Az <- zoo(A$x, A$DayOfYear)
> Bz <- zoo(B$x, B$DayOfYear)
> merge(Az, Bz, fill = 0)
    Az   Bz
1 1429    0
2 3952 3952
3 3049    0
4 2844 2844
5 2219    0
> merge(Az, Bz, fill = 0) %*% c(1, -1)
     [,1]
[1,] 1429
[2,]    0
[3,] 3049
[4,]    0
[5,] 2219


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.
>