[R] Compare matrices

[Dimitris Rizopoulos]

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

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