Re: [R] mask a matrix

From: Liaw, Andy <andy_liaw_at_merck.com>
Date: Sat 11 Jun 2005 - 06:22:50 EST


If you just multiply the two together, you get 0 in the right positions. If you want those to be NAs, just do:

result <- ifelse(A, B, NA)

Andy

> From: Lei Jiang
>
> 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
>
> ______________________________________________
> 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
>
>
>



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 Received on Sat Jun 11 06:27:57 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:32:31 EST