[R] Merge two dataframe with "by", and problems with the common field

[Rainer Schuermann]

Not sure whether this really helps you but at least it works for your sample:

d3 <- merge( d1, d2, by = c(  "a", "b" )  )

> d3                                                                                                                                                                                         
  a b c d  f                                                                                                                                                                                 
1 1 4 5 6  8                                                                                                                                                                                 
2 2 5 6 7  9                                                                                                                                                                                 
3 3 6 7 8 10

Rgds,
Rainer


On Tuesday 07 May 2013 14:33:12 jpm miao wrote:
> Hi,
> 
>    From time to time I merge two dataframes with possibly a common field.
> Then the common field is no longer present,but what are present fieldname.x
> and fieldname.y. How can I fix the problem so that I can still call by the
> orignal fieldname? If you don't understand my problem, please see the
> example below.
> 
>    Thanks
> 
> Miao
> 
> 
> > d1
>   a b c
> 1 1 4 5
> 2 2 5 6
> 3 3 6 7
> > d2
>   d a  f b
> 1 6 1  8 4
> 2 7 2  9 5
> 3 8 3 10 6
> > d3<-merge(d1, d2, by="b")
> > d3
>   b a.x c d a.y  f
> 1 4   1 5 6   1  8
> 2 5   2 6 7   2  9
> 3 6   3 7 8   3 10
> > d3["a"]
> Error in `[.data.frame`(d3, "a") : undefined columns selected
> > d3["a.x"]
>   a.x
> 1   1
> 2   2
> 3   3
> 
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