[R] how to collapse a list of 1 column matrix to a matrix?
François Pinard
pinard at iro.umontreal.ca
Mon Aug 20 05:26:20 CEST 2007
[adschai at optonline.net]
> One more question. After I collapse everything into one matrix,
> I would like to find the index of column that holds minimum value for
> each row. I remember that there is a function like maxCols but I can't
> seem to find the same thing for minimum value. Any suggestion please?
Here is a possible avenue:
> z <- matrix(sample(1:25), 5)
> z
[,1] [,2] [,3] [,4] [,5]
[1,] 16 2 9 24 7
[2,] 21 19 22 23 18
[3,] 12 3 5 13 15
[4,] 20 4 25 11 10
[5,] 17 1 8 14 6
> apply(z, 2, which.min)
[1] 3 5 3 4 5
I would presume (yet I did not recently check) that "do.call",
"which.min", and a flurry of other useful functions, are introduced in
various R tutorials. If you plan to use R seriously, it might be worth
scrutinizing a few of those.
Keep happy!
--
François Pinard http://pinard.progiciels-bpi.ca
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