How to make for loop for subtraction among consecutive array elements ???

Hi , I have one question regarding loop. Let us suppose I have an array a =[2 3 1 8 5 6] Now i want to make a for loop such as in each iteration it proceeds as follows: 1st iteration: 2-3, 2-1,2-8,2-5,2-6.

2nd Iteration: 3-2,3-1,3-8,3-5,3-6 and same as for other iterations.

Can anybody help me out with code snippet for such iterations using for loop. Thanks

Answer 1

[Navdha Agarwal]

Following is the code snippet for the iterations using the for loop.

a =[2 3 1 8 5 6];
len = length(a);    % length of the array, here 6
answer = zeros(len,len-1);
for i = 1:len
    index = 1;
    for j = 1:len
        if(i~=j)
            answer(i,index) = a(i)-a(j);
            index = index+1;
        end
    end
end
disp(answer)

For this question, the answer is stored in the matrix of dimentions 6x5. This is because there are 6 elements and for each element, there will be 5 iterations in its row.

I hope this is helpful.

[Stephen23]

It is much simpler to avoid loops (each column is one "iteration"):

>> a = [2,3,1,8,5,6];
>> m = a(:)-a % or use BSXFUN for version before R2016b.
m =
   0  -1   1  -6  -3  -4
   1   0   2  -5  -2  -3
  -1  -2   0  -7  -4  -5
   6   5   7   0   3   2
   3   2   4  -3   0  -1
   4   3   5  -2   1   0

And optionally remove the diagonal zeros:

>> n = numel(a);
>> m(1:1+n:end) = [];
>> m = reshape(m,[],n)
m =
   1  -1   1  -6  -3  -4
  -1  -2   2  -5  -2  -3
   6   5   7  -7  -4  -5
   3   2   4  -3   3   2
   4   3   5  -2   1  -1