Re: [R] convert vector to matrix

From: David Barron <mothsailor_at_googlemail.com>
Date: Wed 04 Oct 2006 - 22:14:37 GMT

cbind always produces a matrix or data frame. What the FAQ says is that a subsetting operation *on* a matrix will result in redundant dimensions being
dropped, not that you can't get a matrix with a "redundant" dimension as a result of a function.

So,
> vec<-1:10
> vec
 [1] 1 2 3 4 5 6 7 8 9 10
> cbind(vec)

      vec

 [1,]   1
 [2,]   2
 [3,]   3
 [4,]   4
 [5,]   5
 [6,]   6
 [7,]   7
 [8,]   8
 [9,]   9

[10,] 10
> mat<-cbind(vec)
> dim(mat)
[1] 10 1
> mat[,1]

 [1] 1 2 3 4 5 6 7 8 9 10

takes us back to a vector again.

On 04/10/06, Alberto Monteiro <albmont@centroin.com.br> wrote:
> Gavin Simpson wrote:
> >
> > Did you even try to use cbind on your vector? I guess not as,
> >
> > > vec <- 1:10
> > > mat <- cbind(vec)
> > > mat
> >
> Why does mat remain a matrix instead of "losing" one dimension?
> I am reading the FAQ at...
> http://cran.us.r-project.org/doc/FAQ/R-FAQ.html#Why-do-my-matrices-lose-
> dimensions_003f
> ... and it seems that anything you do to mat should turn it back
> into a one-dimensional vector.
>
> Alberto Monteiro
>
> ______________________________________________
> 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.
>

-- 
=================================
David Barron
Said Business School
University of Oxford
Park End Street
Oxford OX1 1HP

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Received on Thu Oct 05 08:21:06 2006

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