Re: [R] transform large matrix into list

From: Stefan Mischke <mischke_at_sozpsy.unizh.ch>
Date: Tue 07 Jun 2005 - 23:28:26 EST

Ok, ok, I got it! Please don't laugh!
My question is the example from the posting guide! Which even includes the answer.
How embarrassing...
Stefan

Am 07.06.2005 um 14:55 schrieb Stefan Mischke:

> Dear List
>
> I need to transform a large matrix M with many NAs into a list L with
> one row for each non missing cell. Every row should contain the cell
> value in the first column, and its coordinates of the matrix in column
> 2 and 3.
>
> M:
> x1 x2
> y1 1 2
> y2 4 5
> y3 7 8
>
> L:
> v x y
> 1 1 1
> 4 1 2
> 7 1 2
> 2 2 1
> 5 2 2
> 8 2 3
>
> I'm trying to do this with a loop, but since my matrix is quite large
> (around 10k^2) this just takes a very long time.
> There must be a more efficient and elegant way to do this. Any hints?
>
> Thanks,
> Stefan
>
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> PLEASE do read the posting guide!
> http://www.R-project.org/posting-guide.html
>



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 Received on Tue Jun 07 23:57:20 2005

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