How to add values through a for loop?

I have a for loop that creates something like this:

first iteration: [1 2 3 4 5 6 7] second iteration: [2 3 4 5 6 7 8] third iteration: [3 4 5 6 7 8 9]

(these aren't my actual values, just an example)

I want my loop to add all of these together at the end. So I would get an output of:

[6 9 12 15 18 21 24]

How can I do this?

Thanks

Answer 1

[Adam]

Just pre-size a vector before the for loop as e.g.

result = zeros( 1, 7 );

then inside the for loop:

result = result + newValues;

where newValues are the results calculated in that iteration. Unfortunately Matlab doesn't have a += operator.

That will add them together as you go. If you really want to only do so at the end then you'd have to store an ( n * m ) matrix for n iterations with length m result and then sum along the relevant dimension.

[Hail]

THANKS!

[Salman Tahir]

what do you mean by " If you really want to only do so at the end then you'd have to store an ( n * m ) matrix for n iterations with length m result and then sum along the relevant dimension."? what is this process called? Is there a place I can look this up?

Answer 2

[Joseph Cheng]

there are two methods. if you need to save each iteration then in the for loop save it like below:

 for iter = 1:3
     %calculations here to get your values A.
     A(iter,:) = randi(10,1,7); % my dummy iteration values
 end
 SumA = sum(A);

if you don't need to save each iteration.

 SumA = 0;
 for iter = 1:3
     %calculations here to get your values A.
     SumA = SumA + randi(10,1,7); % my dummy iteration values
 end

Answer 3

[Salman Tahir]

what do you mean by " If you really want to only do so at the end then you'd have to store an ( n * m ) matrix for n iterations with length m result and then sum along the relevant dimension."? what is this process called? Is there a place I can look this up?