MATLAB: How to create multiple for loops depending on the array size

for loopmultiple for loops

I would like to iterate over multiple for-loops, but the amount of for-loops depends on the size of a vector. Is there a good way to do this, without using a lot of if-statements?
arr = [a1 a2 ... an]
for a1=1:...
   for a2=1:...
       ...
           for an=1:...
               %do something
           end
    end
end
for for examle if the vector arr has "n" entries I would like to have "n" for loops.

Best Answer

As in the answers you find in Stephen's links: Use an index vector instead of a list of for loops. Replace:
arr = [a1 a2 ... an]
for i1 = 1:a1
  for i2 = 1:a2
     ...
         for in = 1:an
             %do something with [i1, i2, ... in]
         end
  end
end
By:
% Loops from 1 to a(n):
n   = length(arr)
ini = ones(1, n);
fin = [a1 a2 ... an];
v     = ini;
iterN = prod(find - ini + 1);  % Number of iterations
for iter = 1:iterN
   % Do something with v
   ...
   % Increase index vector:
   for k = 1:n   % Or n:-1:1, as you want to
      if v(k) < fin(k)
        v(k)  = v(k) + 1;
        break;           % Stop "for k" loop
      end
      v(k) = ini(k);     % Reset this index
   end
end
Related Question