xlswrite - not accepting stored string as valid 'A1' format for Excel

I am currently trying to create a script that will output to Excel a series of 1000x8 matrices. So far my script looks like this, but it is not accepting xlcolo as a valid input and I can't figure out why. If there is an easier way to do this please help out!

xlcol = {'A3'; 'J3'; 'S3'};
xlcoli = {'A'; 'B'; 'C'; 'D'; 'E'; 'F'; 'G'; 'H'; 'I'; 'J'; 'K'; 'L'; 'M'; 'N'; 'O'; 'P'; 'Q'; 'R'; 'S'; 'T'; 'U'; 'V'; 'W'; 'X'; 'Y'; 'Z'};

   %Output to Excel every 1000 trials
    if rem(n,1000) == 0
        a = n/1000;
        if n > 3000
            while a > 3
                a = a - 3;
            end
            xlcolo = sprintf('%c%s',xlcoli(floor(n/3000)),xlcol(a));
        else
            xlcolo = xlcol(a);
        end
        xlswrite(spreadsheet, data, 'Martingale', xlcolo);
        data = zeros(1,8);
    end

I am aware that the code is not lasting beyond 78000 trials at the moment and will have to rectify that in the future. But for the time being I cannot work out why it thinks xlcolo is not a valid 'A1' format. I even tried displaying xlcolo in the command window before running xlswrite and it returned 'A3'.

Any help is greatly appreciated.

Regards,

Sam.

[Mowgli]

Note that the xlcol and xlcoli are not a part of the loop, they are just there so the reader can identify with the variables.

Answer 1

[Sven]

G'day Mowgli,

The problem is that xcolo is a cell, but it's being referenced with parentheses:

xlcol = {'A3'; 'J3'; 'S3'};
xlcolo = xlcol(1);

The code above will return xlcolo(3) as a cell, but you want the contents of xlcolo(3) (ie, a string). Replace:

xlcolo = xlcol(a);

with:

xlcolo = xlcol{a};

and I think you'll be fine.

Note that your sprintf() function also needs to use braces {} to reference xcol otherwise sprintf will error saying "string expected"

[Mowgli]

Thanks for that, this was the first time I have really had to use strings before in MATLAB.