R help - Jul 2009 - match() indexing

Hello,

I'm trying to vectorize some assignment statements using match(), but
can't seem to get it correct.

I have 2 data frames each with a key column of unique values. I want to
copy a column from one frame to another where the key values are the
same.  The data frames are not the same length, and the set of keys is
non-overlapping (each frame has keys not in the other).

Example:
x <- data.frame(id=c(1,3,4,6,7,9,10), r=runif(7))
> x
  id         r
1  1 0.4243219
2  3 0.2389127
3  4 0.7094532
4  6 0.2053836
5  7 0.9630027
6  9 0.1218458
7 10 0.9183175
> y <- data.frame(id=c(1,2,4,7,8,9,10,11,12))
> y
  id
1  1
2  2
3  4
4  7
5  8
6  9
7 10
8 11
9 12

I want to copy the x$r values to y to obtain
>y
  id	r
1  1	0.4243219
2  2	NA
3  4	0.7094532
4  7	0.9630027
5  8	NA
6  9	0.1218458
7 10	0.9183175
8 11	NA
9 12	NA

xIdx <- match(x$id,y$id) yields a vector of length x, so it cannot be
used directly to copy to y. 

Any help in vectorizing this assignment would be most welcome.

Chris

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Dear Christopher,
Try this:

merge(x,y,all=TRUE)

HTH,

Jorge


On Wed, Jul 1, 2009 at 2:51 PM, Hane, Christopher A <
christopher.hane@ingenixconsulting.com> wrote:
>
>  Hello,
>
> I'm trying to vectorize some assignment statements using match(), but
> can't seem to get it correct.
>
> I have 2 data frames each with a key column of unique values. I want to
> copy a column from one frame to another where the key values are the
> same.  The data frames are not the same length, and the set of keys is
> non-overlapping (each frame has keys not in the other).
>
> Example:
> x <- data.frame(id=c(1,3,4,6,7,9,10), r=runif(7))
> > x
>  id         r
> 1  1 0.4243219
> 2  3 0.2389127
> 3  4 0.7094532
> 4  6 0.2053836
> 5  7 0.9630027
> 6  9 0.1218458
> 7 10 0.9183175
> > y <- data.frame(id=c(1,2,4,7,8,9,10,11,12))
> > y
>  id
> 1  1
> 2  2
> 3  4
> 4  7
> 5  8
> 6  9
> 7 10
> 8 11
> 9 12
>
> I want to copy the x$r values to y to obtain
> >y
>  id    r
> 1  1    0.4243219
> 2  2    NA
> 3  4    0.7094532
> 4  7    0.9630027
> 5  8    NA
> 6  9    0.1218458
> 7 10    0.9183175
> 8 11    NA
> 9 12    NA
>
> xIdx <- match(x$id,y$id) yields a vector of length x, so it cannot be
> used directly to copy to y.
>
> Any help in vectorizing this assignment would be most welcome.
>
> Chris
>
> This e-mail, including attachments, may include confidential and/or
> proprietary information, and may be used only by the person or entity
> to which it is addressed. If the reader of this e-mail is not the intended
> recipient or his or her authorized agent, the reader is hereby notified
> that any dissemination, distribution or copying of this e-mail is
> prohibited. If you have received this e-mail in error, please notify the
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