How can I assign values to elements with same index from multiple cells?

I have a cell array with the same-size matrix in each cell, say,

a = cell(2);

[a{:}]=deal(rand(2));

and I want to change the first element of the matrix in each cell to values 1,2,3 and 4 respectively. Something equivalent to

a{:}(1,1) = 1:4;

would be ideal however this syntax doesn't work. Is there any other way?

[Walter Roberson]

I don't think this can be done with this kind of syntax.

[Stephen23]

The best solution is to avoid cell arrays and use multi-dimensional numeric arrays. then this task is trivial to achieve. See Guillaume's answer for an example of how to do this.

Answer 1

[Guillaume]

Matlab is not clever enough to expand inner indexing into outer cells (plus there's no guarantee it would work, some cells may not even have 4 elements). So you have to do it yourself and you don't have a choice but to use a loop:

vals = 1:4;
for idx = 1:numel(a)
  a{idx}(1) = vals(idx);
end

However, if all the matrices are the same dimension, you could simply convert your cell array to a matrix, which then lets you use normal indexing. With your example:

alla = cat(3, a{:});
alla(1, 1, :) = 1:4;
%and if you want it back as a cell array
a = reshape(num2cell(alla, [1 2]), size(a))

Answer 2

[Stalin Samuel]

[r c] = size(a);
val = 0;
for n1 = 1:r
    for n2 = 1:c
        val = val+1;
        a{n1,n2}(1,1) = val;
    end
end

Answer 3

[Hamid Arbabi]

Thank you guys for the comments and answers. I think I will go with Guillaume's suggestion of using multidimensional arrays.

Hamid