Re: [R] Problem with allp ossible combination.

From: Jacques VESLOT <jacques.veslot_at_good.ibl.fr>
Date: Mon 31 Jul 2006 - 19:02:14 EST

diffs <- do.call(expand.grid, dt)
diffs$delta <- rowSums(expand.grid(dt$a, -dt$b))



Jacques VESLOT

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Arun Kumar Saha a écrit :
> Dear R Users,
>
> Suppose I have a dataset like this:
>
> a b
>
> 39700 485.00
> 39300 485.00
> 39100 480.00
> 38800 487.00
> 38800 492.00
> 39300 507.00
> 39500 493.00
> 39400 494.00
> 39500 494.00
> 39100 494.00
> 39200 490.00
>
> Now I want get a-b for all possible combinations of a and b. Using two 'for'

> loop it is easy to calculate. But problem arises when row length of the data
> set is large eg. 1000 or more. Then R takes lot of time to do that. Can
> anyone please tell me whether there is any R-function to do such kind of job
> quickly?
>
> Thanks and regards,
>
> [[alternative HTML version deleted]]
>
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> and provide commented, minimal, self-contained, reproducible code.
>



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Mon Jul 31 19:12:44 2006

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