Finding and setting new values for matrix elements within a cell array

I have several large cell arrays (e.g., 9x9 cell) where each cell is composed of a large matrix (e.g., 800x200 double). I'd like to find all of a certain type of element within each matrix in each cell and set it equal to a new value. I'm asking this in a general form because I've run into this problem on many occasions now, but just for example, all elements equal to 0 or NaN.

I can do this easily for data in a matrix:

x = [0:10,NaN];
x(x==0) = 1;
x(isnan(x)) = 11;

but I haven't been able to find an elegant way to do the same thing when the data is in cells. This is as far as I've gotten:

a = {[0:5] [5:10,NaN];[10:20] [zeros(5,8)]};
ind = cellfun(@(elem)elem==0,a,'uniform',0); %generates a logical array indexing the elements I want in each cell
cellfun(@(a,ind)a(ind),a,ind,'uniform',0); %returns cell array containing only the values I want to reference from each cell

but I'm trying for something like the following, which won't work:

cellfun(@(a,ind)a(ind)=1,a,ind,'uniform',0); %set ind elements of all cells in a equal to 1

I do realize I can accomplish what I'm trying to do with for loops:

for i = 1:size(a,1)
  for j = 1:size(a,2)
    a{i,j}(a{i,j}==0) = 1;
  end
end

but this is more of a question about whether it's even possible to do what I want to do (there are also several cases in my data where a for loop like this would be clunky and I would legitimately really like to be able to do this in just one line). Any help would be much appreciated, thanks!

Answer 1

[Stephen23]

The simplest and most efficient solution is to use a for loop.

But then you write "...there are also several cases in my data where a for loop like this would be clunky and I would legitimately really like to be able to do this in just one line". Okay, then lets do this in one line by defining a function:

function x = myfun(x)
x(x==0) = 1;
x(isnan(x)) = 11;
end

and then calling it using cellfun:

C = cellfun(@myfun,C,'uni',0)

You could easily parametrize the function to match/replace different values:

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

Using a nested function is another option, which might be an advantage if the arrays are large.