Add more nan values

I have a matrix which may contains a region of nan values. I would like to surround the nan region with 0 boundary.

An example

A = 5 5 5 5; 5 5 nan 5; 5 5 5 5;

would become 5 0 0 0 ; 5 0 nan 0; 5 0 0 0;

Any help is appreciated

[Jan]

What should happen for two neighboring NaNs?

Answer 1

[Youssef Khmou]

hi try this standard version :

 % Given 

 A = [5 5 5 5; 5 NaN 5 5; 5 5 5 5];

 [N]=size(A);

 for x=2:N(1)-1
  for y=2:N(1)-1

        if isnan(A(x,y))     
        %A(x-1:x+1,y-1:y+1)=0; not operational solution
        A(x-1:x+1,y-1)=0;
        A(x-1:x+1,y+1)=0;
        A(x-1,y)=0;
        A(x+1,y)=0; 
        end
end
 end
A