Re: [R] mask a matrix

From: Mwalili, S. M. <samuel_mwalili_at_yahoo.com>
Date: Sat 11 Jun 2005 - 06:26:57 EST


Jiang,
This example could help:  

A <- matrix(rbinom(20,1,.8),ncol=2)
B <- cbind(rnorm(20,-1,0),rnorm(20,1,0))
B <- ifelse(A==0,NA,B)

B
A    

S M Mwalili.

Lei Jiang <lj22@u.washington.edu> wrote: Hi, there.

I have two matrix with identical dimentions. matrix A contains information of 0 and 1, and matrix B contains data. I only want the data in matrix B where matrix A has 1's. the places where matrix A has 0's, I want NA's in matrix B.

How do I do that??

Thank you very much.

Lei Jiang

Department of Chemsitry
University of Washington
Box 351700
Seattle, WA 98195
Phone: 206-616-6882
Fax: 206-685-8665



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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 Received on Sat Jun 11 06:31:48 2005

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