How to make a matrix mirror another?

How do I do this?

X=[4 7 1 0;
   3 0 6 8] 
Y=[32 6 4 21;
   77 89 0 2]
X(X==0)=a;

after the alteration:

X=[4 7 1 a;
   3 a 6 8]    

Y=[ 32 6 4 a;
   77  a  0  2];

[Adam Danz]

Please explain in words what you'd like to do.

[Image Analyst]

Why are the non-zero locations of X changing, and why are the elements of Y changing???

Anyway, you answered your own question. You simply ignore the original X and make the assignment:

a = 99; % Whatever....
X=[3 a 4 6;
   1 7 8 a]         
Y=[77 a 32 0;
   4  6  2  a]

There. You're done.

[Hugo Matias]

My bad, fixed it

[Hugo Matias]

I can't do it that way.

I can't do manual alterations on Y.

Y has to change exactly how X changes, automatically

Answer 1

[Star Strider]

Try this:

a = 42;
X=[4 7 1 0;
   3 0 6 8] 
Y=[32 6 4 21;
   77 89 0 2]
Idx = X==0
X(Idx) = a
Y(Idx) = a                         % Use The Same Index On Both Matrices,

[Hugo Matias]

Thank you sir

[Star Strider]

As always, my pleasure.

[Hugo Matias]

By the way, do you know how to do this one?

(sort the matrix)

before:

a=[3 9 5 7;

3 0 1 2;

11 2 0 9];

after:

a=[11 9 9 7;

5 3 3 2;

2 1 0 0;]

[Star Strider]

Yes!

a=[ 3 9 5 7;
    3 0 1 2;
   11 2 0 9];

a_after = reshape(sort(a(:),'descend'), 4, [])'

a_after =
    11     9     9     7
     5     3     3     2
     2     1     0     0

My apologies for the delay. I didn’t see your comment before.