Octave - Adding '\n' to String Array is Not Creating a New Line

Question

I want to change ',' character to '\n' and save it to the text file

All files are in this format:

546,234,453,685,.....,234

I want to make it like:

546

234

453

685

...

234

My initiation to this problem is like this:

fid=fopen(files{i});
strArr=fscanf(fid,'%s');

newstrArr=strrep(strArr,',','\n');

% Take each .txt input
for j=1:length(newstrArr)  
   Array=[Array newstrArr(j)];   
endfor

Let me explain step by step:

1st I open the current text file

 fid=fopen(files{i});

2nd I find the strings in text file

strArr=fscanf(fid,'%s');

Please Note that you can't replace %s with %d. (Correct me if I am wrong)

3rd I replace commas with newline character

newstrArr=strrep(strArr,',','\n');

4th I add each character to a new array with for loop

for j=1:length(newstrArr)  
   Array=[Array newstrArr(j)];   
endfor

However When I display, using;

disp(Array);

I have this output

How can I properly replace the commas with newlines?

Regards

Answer 1

The issue is that you are inserting a literal '\n' (the characters \ and n) and not a newline character. This is because in Octave, a single-quote enclosed string ignores escape sequences. If you want Octave to respect escape sequences you could use a double-quoted string which will convert \n into a newline.

strrep(strArr, ',', "\n");

Or if you want your code to be MATLAB-compatible, you'll want to instead use char(10) (an actual new-line character). This is because MATLAB does not have double-quote enclosed strings.

output = strrep(strArr, ',', char(10));

Another option would be to split your input at the , and use sprintf to add the newlines (it'll treat \n as a newline)

values = strsplit(strArr, ',');
output = sprintf('%s\n', values{:});

If you just want to save each entry to a new line in a file, you can use fprintf instead.

values = strsplit(strArr, ',');
fout = fopen('output.txt', 'w');
fprintf(foug, '%s\n', values{:});
fclose(fout);

Answer 2

If you really just want to replace "," with newline simply do

in = fileread ("yourfile");
out = strrep (in, ",", "\n")
out = 546
234
453
685
234

Btw, see the difference between "\n" (in GNU Octave a newline) and '\n' (literally \n)

Answer 3

Another option is to use regexprep(), this has the advantage of being MATLAB compatible. Assuming that the newline convention you want is \n, then

regexprep('123,456,789',',','\n')

ans = 123
456
789

When output to a file via fprintf() the result looks like

123
456
789

provided the text editor understands the newline convention.