[R] Data length mismatch.

[Gabor Grothendieck]

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
>>
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>