[R] Merging data.frames

[Tony Plate]

 > d1 <- data.frame(val1=c(A=1,B=3,C=5),val2=c(2,4,6))
 > d1
   val1 val2
A    1    2
B    3    4
C    5    6
 > d2 <- data.frame(val3=c(A=1,C=2,D=3),val4=c(4,5,6))
 > d2
   val3 val4
A    1    4
C    2    5
D    3    6
 > merge(d1, d2, by="row.names")
   Row.names val1 val2 val3 val4
1         A    1    2    1    4
2         C    5    6    2    5
 >

At 04:05 PM 11/8/2002 -0500, Paul Boutros <pcboutro at engmail.uwaterloo.ca> 
wrote:
>Is it possible to combine two data-frames, just taking the rows where
>these frames have equivalent names?
>So for example I would want to take:
>
>d1:
>   val1 val2
>A  1    2
>B  3    4
>C  5    6
>
>and d2:
>   val3 val4
>A  1    4
>C  2    5
>D  3    6
>
>to merge into:
>   val1 val2 val3 val4
>A  1    2    1    4
>C  5    6    2    5
>
>Is this kind of "merge on equal rows" to create a subset of the two
>data-frames possible in R, or would I need to move to an altnerate
>lagnauge to do this?
>
>Thanks for any ideas!
>Paul
>
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-- solution found after a lengthy and arduous perusal of the 
difficult-to-locate documentation for the merge function :-)

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