At 05:07 30/03/2009, Aaron M. Swoboda wrote:
I would like to know which rows are duplicates of each other, not
simply that a row is duplicate of another row. In the following
example rows 1 and 3 are duplicates.
> x <- c(1,3,1)
> y <- c(2,4,2)
> z <- c(3,4,3)
> data <- data.frame(x,y,z)
x y z
1 1 2 3
2 3 4 4
3 1 2 3
Does this do what you want?
> x <- c(1,3,1)
> y <- c(2,4,2)
> z <- c(3,4,3)
> data <- data.frame(x,y,z)
> data.u <- unique(data)
> data.u
x y z
1 1 2 3
2 3 4 4
> data.u <- cbind(data.u, set = 1:nrow(data.u))
> merge(data, data.u)
x y z set
1 1 2 3 1
2 1 2 3 1
3 3 4 4 2
You need to do a bit more work to get them back into the original row
order if that is essential.
I can't figure out how to get R to tell me that observation 1 and 3
are the same. It seems like the "duplicated" and "unique" functions
should be able to help me out, but I am stumped.
For instance, if I use "duplicated" ...
> duplicated(data)
[1] FALSE FALSE TRUE
it tells me that row 3 is a duplicate, but not which row it matches.
How do I figure out WHICH row it matches?
And If I use "unique"...
> unique(data)
x y z
1 1 2 3
2 3 4 4
I see that rows 1 and 2 are unique, leaving me to infer that row 3 was
a duplicate, but again it doesn't tell me which row it was a duplicate
of (as far as I can tell). Am I missing something?
How can I determine that row 3 is a duplicate OF ROW 1?
Thanks,
Aaron
Michael Dewey
http://www.aghmed.fsnet.co.uk
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