How can I cancel ("NaN" value) elements of a matrix based on another matrix's "NaN" values?

Hi everyone,

Let's suppose I have a matrix A: A = 1 2 3; 4 5 6; 7 8 9

and a matrix B: B= 1 NaN 3; NaN 5 6; 7 NaN NaN

I want to cancel the same elements that are canceled in matrix B. It would be:

A2= 1 NaN 3; NaN 5 6; 7 NaN NaN

How can I do that?

Answer 1

[OCDER]

Use isnan to find where NaN values are. Then replace elements in A with NaN to get A2.

A2 = A;
A2(isnan(B)) = NaN;

A2 =
   1   NaN     3
 NaN     5     6
   7   NaN   NaN

Answer 2

[Andrei Bobrov]

A2 = B./B.*A

[Stephen23]

Cute, but fails for Inf values in B.