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Message-ID: <1351643648.65946.YahooMailNeo@web142604.mail.bf1.yahoo.com>
Date: 2012-10-31T00:34:08Z
From: arun
Subject: Swap rows and columns in a matrix
In-Reply-To: <7EC32370-97E5-4DDF-AED2-CE3DE8BF20D2@comcast.net>

HI David,

Seems like a closing bracket is needed.

mat[, sample(dim(mat)[2]) ]

?????????????????????????????????????? ^^^
A.K.




----- Original Message -----
From: David Winsemius <dwinsemius at comcast.net>
To: Haris Rhrlp <haris_r_help at yahoo.com>
Cc: "R-help at r-project.org" <R-help at r-project.org>
Sent: Tuesday, October 30, 2012 6:51 PM
Subject: Re: [R] Swap rows and columns in a matrix


On Oct 30, 2012, at 11:59 AM, Haris Rhrlp wrote:

> Dear R users,
> 
> I want a help to write an algorithm for swapping rows and columns in a matrix
> 

This will "shuffle" columns, although 'randomly permute' is the more common word for this;operation:

set.seed(123)
mat[, sample(dim(mat)[2] ]

This will swap rows:

set.seed(123)
mat[ sample(dim(mat)[1],? ]

-- 
David Winsemius, MD
Alameda, CA, USA

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