How to store data whose dimension varies at each steps of run?

I have a program, let say it runs for N times. So say b=1:N. Now at each iteration I get an array A whose size varries in the order of 1 by M where M is unknown (created by the nature of the pogramme). M changes with the change of iteration. Now my question is how to store this type of inodrmation in the following format or any other. For example,

b  data
1  1 
2  1 2 3
3  1 4 5 6
4  8

and so

Answer 1

[Scott MacKenzie]

This is a bit long-winded (and can surely be shortened), but I think it achieves what you are looking for:

N = 8; % iterations
M = 5; % array size varies from 1 to 5 randomly in each iteration

% save the data in cell array C
C = {};
for b=1:N
    
    % generate the numbers for this iteration (numbers and array size varies)
    A = randi(9,1,randi([1 M])); 
    
    % convert numbers to cell array and store in C
    C{b} = num2cell(A); 
end
% we're done (data in C)

% output the data saved
fprintf('%2s %5s\n', 'b', 'data');
for i=1:N
    fprintf('%2d  ', i);    
    fprintf('%d ', cell2mat(C{i}));   
    fprintf('\n');
end

Output:

b data

1 6 7 6

2 7 8

3 1 2 3 1

4 9 4 8 3

5 2 4 6

6 4

7 6

8 2 8 3 1 7

[Souarv De]

Thank You Scott.