[R] Randomly selecting rows with unique values in two columns
David Winsemius
dwinsemius at comcast.net
Tue Sep 27 02:53:43 CEST 2011
On Sep 26, 2011, at 5:42 PM, hasan wrote:
> Hello,
>
> I am trying to randomly select rows with unique values in columns 1
> and 2. I
> want to generate multiple subsets to estimate a statistic for each
> data set.
> Below is a simplified example.
>
> L1 L2 L3 L4 L5
> 1 a b 1 2 3
> 2 a c 4 5 6
> 3 a d 7 8 9
> 4 a e 10 11 12
> 5 a f 13 14 15
> 6 b c 16 17 18
> 7 b d 19 20 21
> 8 b e 22 23 24
> 9 b f 25 26 27
> 10 c d 28 29 30
> 11 c e 31 32 33
> 12 c f 34 35 36
> 13 d e 37 38 39
> 14 d f 40 41 42
> 15 e f 43 44 45
I think this is isomorphic to a question in the last couple of days on
StackOverflow:
http://stackoverflow.com/questions/7536218/how-do-i-take-subsets-of-a-data-frame-according-to-a-grouping-in-r-tricky-aggre/7536610#7536610
(I don't think the -1 score on my tapply solution is exactly fair. but
I suspect that Ari has moved on to other things and is not going back
to check up on edits. I think w=either solution should provide a
random selection within groups.)
>
> Could you please give directions to where to start? I have tried
> eliminating
> duplicates and finding unique rows but no successful to make it
> random.
>
> Thanks
>
> Hasan
>
> --
> View this message in context: http://r.789695.n4.nabble.com/Randomly-selecting-rows-with-unique-values-in-two-columns-tp3845504p3845504.html
> Sent from the R help mailing list archive at Nabble.com.
>
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David Winsemius, MD
West Hartford, CT
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