Re: [R] curious about dimension of 'apply' output when MARGIN=1

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Wed 17 Jan 2007 - 00:16:56 GMT

The reshape package has an idempotent apply, iapply:

> library(reshape)
> iapply(M,1,function(row) row+c(1,2))

     [,1] [,2]

[1,]    2    6
[2,]    3    7
[3,]    4    8

On 1/16/07, Benjamin Tyner <btyner@stat.purdue.edu> wrote:
> Reading the documentation for 'apply', I understand the following is
> working exactly as documented:
>
> > M<-matrix(1:6,ncol=2)
> > M
> [,1] [,2]
> [1,] 1 4
> [2,] 2 5
> [3,] 3 6
> > apply(M,2,function(column) column+c(1,2,3))
> [,1] [,2]
> [1,] 2 5
> [2,] 4 7
> [3,] 6 9
> > apply(M,1,function(row) row+c(1,2))
> [,1] [,2] [,3]
> [1,] 2 3 4
> [2,] 6 7 8
>
> I'm not proposing any changes or extra arguments to 'apply'. Rather, I'm
> wondering what is the benefit for (or rationale behind) this somewhat
> unintuitive behavior in the case that MARGIN=1.
>
> Thanks,
> Ben
>
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>



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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 Wed Jan 17 11:23:23 2007

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