Writing data in file and naming file with a string value

Hi..

My simulations are finding errors for 4 cases in a loop as shown below. I am writing those errors in data file.

Problem is naming of the file. I want to name my files as error_200.txt, error_400.txt, error_800.txt and error_1600.txt respectively for each case. For that i have to mention the 'n' which contains different values in each loop, in the file name.

something like :fileID = fopen('error_'n'.txt','a') so that file will be automatically generated with the value of n in the name. Here is the code.............

for i = 1:4,

k = 2^i ;

n = k*100

    for step = 1:1000

        % here some calculations happen and data is generated,
        % and i write those date (error) in a file.

        error = n % for example

        D = [step; error;];
        fileID = fopen('error_'n'.txt','a');
        fprintf(fileID,'%6.2f %12.4f\n',D);
        fclose(fileID);

    end

end

Currently it writes all the data in single file. Pl help me modify the code to include the value of 'n' filename while writing the data so that 4 different file are generated with different names.

 Thanks.

Answer 1

[Yoav Livneh]

Change your fopen line to:

fileID = fopen(['error_', num2str(n), '.txt'],'a');

[RS]

Hey, thankyou so much. It worked.

[RS]

One more question. I am plotting figure in each loop. Can the figure be named with the figure name as 'n' thereby generating 4 different figures.

I tried:

 figure(num2str(n))
 plot(step,error);

It showed an error.

[Yoav Livneh]

Just use

figure(n);
plot(step,error);

or just

figure;
plot(step,error);

The first option will always use the same four figures and overwrite the previous plots, the second option will always create new figures.

[RS]

Thanks.