XLSwrite function

Hello, I am trying to export the results of my code into an excel file using the xlswrite function. However, instead of having 17520 different values, it just plots the first value into all excel cells. Can anyone help?

Here is my code;

function [d] = DOC_export

b = xlsread( 'Cumulative_flow.xlsx',1,'B2:B17521');

c = xlsread ('Cumulative_flow.xlsx',1, 'C2:C17521');

for i = 1:17518;

    d(1) = b(1)*c(1);

      d(i+1) = (b(i+1)-b(i)) * c(i+1);

      d(17520) = (b(17520)-b(17519))*c(17520);

end

e = d;

xlswrite ('Cumulative_flow.xlsx',e,1,'D2:D17521')

Answer 1

[John Kitchin]

You need to transpose e:

xlswrite ('Cumulative_flow.xlsx',e',1,'D2:D17521')

alternatively, create your d vector in the same shape as b and c before you enter the loop:

d = zeros(size(c));

so it is created as a column. It looks like you could take the first and third lines out of your loop, since they don't depend on the loop counter. No point in calculating them 17518 times each!

[John Kitchin]

hehe... someone else posted the same thing while I was writing my answer!

[Maeve Ryan]

Thanks that worked!

Answer 2

[Fangjun Jiang]

The problem is:

Your resulting e is 1x17520, a row vector. Your specified position is 'D2:D17521', a column vector.

This could be an improvement of xlswrite. But anyway, that is the cause of the problem. If you write the transpose of e, the result will be correct. xlswrite ('Cumulative_flow.xlsx',e',1,'D2:D17521')

Or you can directly pre-allocate d as a column vector d=zeros(17520,1)

Two other things:

1. You should pre-allocate d as above, because d is a pretty large vector.
2. You need to move the first and third line inside the for-loop out of the loop.

[Maeve Ryan]

Okay thanks that works perfectly. What do you mean by pre-allocating d?

Thanks