Compare matrices
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
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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 ______________________________________________ R-help at r-project.org 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.