[R] Compare matrices

[Steven McKinney]

Use the is.na() function to assign
NA values:


> is.na(A) <- !B
> A
     [,1] [,2] [,3]
[1,]    3   NA   NA
[2,]    3    3    3
[3,]    3    3   NA
> C <- matrix(c(3,3,3,NA,3,3,NA,3,NA),3,3)
> all.equal(A, C)
[1] TRUE





Steven McKinney

Statistician
Molecular Oncology and Breast Cancer Program
British Columbia Cancer Research Centre

email: smckinney +at+ bccrc +dot+ ca

tel: 604-675-8000 x7561

BCCRC
Molecular Oncology
675 West 10th Ave, Floor 4
Vancouver B.C. 
V5Z 1L3
Canada




-----Original Message-----
From: r-help-bounces at r-project.org on behalf of Dimitris Rizopoulos
Sent: Mon 1/19/2009 12:54 PM
To: Andrej Kastrin
Cc: r-help at r-project.org
Subject: Re: [R] Compare matrices
 
try this:

A <- matrix(c(3,3,3,3,3,3,3,3,3),3,3)
B <- matrix(c(T,T,T,F,T,T,F,T,F),3,3)

C <- A
C[!B] <- NA
C


I hope it helps.

Best,
Dimitris


Andrej Kastrin wrote:
> Dear all,
> 
> Suppose that I have a matrix A
> 
>    A <- matrix(c(3,3,3,3,3,3,3,3,3),3,3)
> 
> and a logical matrix B
> 
>    B <- matrix(c(T,T,T,F,T,T,F,T,F),3,3)
> 
> The result  matrix should be
> 
>    C <- matrix(c(3,3,3,NA,3,3,NA,3,NA),3,3)
> 
> Is there any simple tip or trick to perform this without looping?
> 
> Thanks in advance for any suggestion.
> 
> Best regards, Andrej
> 
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 

-- 
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014

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and provide commented, minimal, self-contained, reproducible code.