Why dlmread do not work with dlmwrite?

hi, I wrote symbols to file using dlmwrite, where the file became:

?,R,M,G,f,D,[],[]

W,E,R,R,T,U,H,K

N,D,F,[],[],[]

when tried to read it with dlmread , I got :

 ??? Error using ==> dlmread at 145
Mismatch between file and format string.
Trouble reading number from file (row 1, field 1) ==> ?,R,K

thanks

[Jan]

Please post the code you have been using for writing and reading.

[huda nawaf]

simple ex.

x=['qwe', 'ert','jkl';'rty', 'yui','oip'];

dlmwrite('f.txt',x);

d=dlmread('d:\matlab11\r2011a\bin\f.txt')

??? Error using ==> dlmread at 145

Mismatch between file and format string.

Trouble reading number from file (row 1, field 1) ==> q,w,e

[huda nawaf]

simple ex.

x=['qwe', 'ert','jkl';'rty', 'yui','oip'];

dlmwrite('f.txt',x);

d=dlmread('d:\matlab11\r2011a\bin\f.txt')

??? Error using ==> dlmread at 145

Mismatch between file and format string.

Trouble reading number from file (row 1, field 1) ==> q,w,e

[Walter Roberson]

As already explained, but I have expanded my answer to discuss this pointer further.

Answer 1

[Walter Roberson]

dlmread() can only read numeric data.

You have to cheat with dlmwrite() in order to write character data with it: it is not designed to write characters.

I did firmly say that I do not recommend that you use dlmwrite() to write character data, and that I only came up with the method to be contrary when someone said that it could not be done. I think I showed the code for the fopen / fprintf / fclose alternative.

[added]

When I said that dlmread can only read numeric data, I meant exactly that. It states this clearly in the documentation:

http://www.mathworks.com/matlabcentral/answers/23570-why-dlmread-do-not-work-with-dlmwrite

Tips

    All data in the input file must be numeric. dlmread does not read files that contain nonnumeric data, even if the specified rows and columns contain only numeric data.

I have also examined the code that it uses; it uses an undocumented facility, but there is no doubt through testing that the facility will ONLY read numeric data.