Export martrix to excel in Loop

I have a FOR loop in my code and need to save Result ( vertcat of A and B ) in ONE Excel file in new Row(every columns are same) ,but MATLAB save them (each step) in new Excell file !

for Example:

for i=1:5
  A=ones(2,5);
  B=zeros(3,5);
  xlswrite('testdata.xls',[A;B]);
  i=i+1;
end

can you help me

[dpb]

Simplest is to build the entire array in memory and then xlswrite only once after the loop.

Alternatively, you've got to build a dynamic range argument to place the new section where it belongs; what you've told it to do is to write each time starting at cell A1.

[Isay]

can you say an example ?

my REAL matrix have 1million Rows and 6000 column! I can't build it in memory!

[dpb]

Excel can't handle that size an array anyway, can it?

[Isay]

i guess yes!

[dpb]

Just because the limitations on the number of rows or columns is greater than the limit, that doesn't necessarily mean Excel has any more system memory than does Matlab...I'd guess 48GB is likely going to bring it to its knees as well...or even if not if it actually will try to page, virtual memory paging will kill you. I don't really think Excel is any "more smarter" than Matlab will be on handling this much data. I don't have 64-bit OS so can't really test it, but just sayin'...

[Isay]

please forget 1million Row and other things, and look at my message: i need to Edit " xlswrite('testdata.xls',[A;B]);" to vaertcat A and B UNDER each other in each STEP of Loop. IN ONE EXCEL FILE Just it !

can you Edit for me ?

Answer 1

[Image Analyst]

If you can't fit the 1,000,000 x 6,000 array (48 GB) in memory, then you have to use ActiveX to send it to Excel. See attached demo.

[Isay]

it's faild .

can you send to me A simple code of it ?

[Image Analyst]

How did it fail? What was the error message?

[Isay]

error at line 89 .

please forget 1million Row and other things, and look at my message: i need to Edit " xlswrite('testdata.xls',[A;B]);" to vaertcat A and B UNDER each other in each STEP of Loop. IN ONE EXCEL FILE Just it !

can you Edit for me ?

[Image Analyst]

Try to increase the row each time

numberOfRows = size(A, 1) + size(B, 1);
thisRow = (i-1)*numberOfRows + 1;
cellReference = sprintf('A%d', thisRow);
xlswrite('testdata.xls',[A;B], cellReference);

[Isay]

thanks, But your code Add sheet in each step of (For) loop. I need all of them in ONE Sheet.

[Image Analyst]

Isay, I don't know why it does that - according to the help it should not. But try this - it works:

delete('testdata.xls'); % Delete any prior file.
for i=1:5
  A=ones(2,5);
  B=zeros(3,5);
  numberOfRows = size(A, 1) + size(B, 1);
  thisRow = (i-1)*numberOfRows + 1
  cellReference = sprintf('A%d:E%d', thisRow, thisRow + numberOfRows-1)
  xlswrite('testdata.xls',[A;B], cellReference);
end

Answer 2

[Moh]

try

idx = 0;
for i=1:5
  A=ones(2,5);
  B=zeros(3,5);
  [C,D]=size([A;B]);
  xlswrite('testdata.xls',[A;B],1,strcat('A',num2str(1+idx)));
  idx = idx+C;
end