[R] Data length mismatch.

[Gabor Grothendieck]

For the last statement we may prefer this
so it stays a zoo object:

> m <- merge(Az, Bz, fill = 0)
> m[,1] - m[,2]
   1    2    3    4    5
1429    0 3049    0 2219

On Sat, Jul 26, 2008 at 5:53 PM, Gabor Grothendieck
<ggrothendieck at gmail.com> wrote:
> 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
>>
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>