fprintf doesn't create new lines

Output txt file is a single row of text, ignoring the fprintf new line command. I have checked the file in the matlab editor, notepad, and several different other text editors, and all show the same.

I have tried \n, \r, \r\n, \n\r. None produces a new line. I have also set the fopen as 'wt' and 'at' (following similar questions here), none of them work.

Have tried it in mac and windows, same results

Is there an actual solution for this issue?

Currently working on mac (capitan) on matlab 2015a; but I have the same issue in windows and matlab 2014

[Stephen23]

@D.: please show us a MWE (minimum working example) so that we can replicate this behavior.

[D.]

file = fopen(filename,'wt');
fprintf(file,'%d\n', text)

[José-Luis]

That's not a working example. What's in text? It might be that there actually is only one newline character at the end of all your text, which is perhaps not the behavior you wanted.

[D.]

text is a variable. The code is supposed to create a new line writing the content of several variables (each one tab separated), create a new line, and repeat. Each line represents a particular combination of variables, but that is not the point. The fact is that everything is written to the file adequately, except that it doesnt create new lines. Interesingly enough, the exact same code was working fine 2 months ago, but now all of a sudden it doesn't, without making any changes to the script, or Matlab, or the computer where the script is executed.

[José-Luis]

"text is a variable" is not a very helpful statement...

[Stephen23]

"The code is supposed to create a new line writing the content of several variables (each one tab separated), create a new line, and repeat"

The format string will "repeat" until there are no more values left. Your code only includes one \n newline, and your (very vague) description of text does not give us any reason to believe that this format string would be applied multiple times.

text is one variable, so where are these "several variables" that you mention ?

There is most likely a bug in your code. When you provide us with a MWE (as I originally requested but you have failed to do), then we can help you to resolve this.

[D.]

I was not expecting the specific content of the output would matter that much... Lets say text == "A", and I want a (vertical) list of A's, and instead I get a succession of A's in a row. In the real script, each line is composed, like I said, of several variables (numeric or strings), separated by tabs. And again, the output of the fprintf looks perfectly fine, except for the fact that no new lines are created.

[Stephen23]

"Lets say text == "A""

There is no way that you could get a succession of A's using text='A' and your format string:

>> fprintf(1,'%d\n','A')
65

This does however correctly print the character value of 'A' and one newline, as it should. I don't see why you would expect it to produce multiple A's in a column though.

"each line is composed, like I said, of several variables (numeric or strings), separated by tabs"

Which "variables"? You only showed us one: the badly named text. You should never call any variable text, because this is the name of a very important inbuilt function text.

Please show us a complete Minimum Working Example. Please. Three times asking for the same thing is my limit.

[Rena Berman]

(Answers dev) restored question

Answer 1

[Thorsten]

You can fprint to fid == 1 to view the result on the console for testing. This creates newlines

fprintf(1,'%d\n', [1 2 3])

[D.]

Thanks for the fid ==1 tip! that is indeed useful for testing.

Answer 2

[D.]

Copy / pasted script to an external text editor, and then copy/pasted it back from there to matlab editor (To be sure, no editing at all was done between copy/paste operations). Now the output file looks as expected. FYI.

Answer 3

[Matthew Cooper]

If you are writing to a file recursively, you may need to substitute 'a' for 'w' on fopen:

fopen(fid,'foo.txt','w');
fprintf(fid,formatspec,text);
fclose(fid);
fopen(fid,'foo.txt','a');
fprintf(fid,formatspec,newtext);

[Walter Roberson]

This is not relevant to the user's question.

[Matthew Cooper]

Not everyone asks perfect questions. When I searched for an answer to why I could not make \n work, I found this thread. My answer provided the solution. I don't think my answer is doing any harm, but thank you for taking the time to comment.

[Walter Roberson]

When 'r' is used, any existing file content is not removed during fopen(). Requests to write content are ignored (no error message.)

When 'w' is used, any existing file has its contents completely removed during the fopen(). The file does not have to already exist. Any new content written, would be written at the "current position", which would start out being at the end of the emptied file (which is the same as the beginning of the emptied file, since the file is empty), but could be changed with fseek(). If the writing that produces the furthest writing into the file does not end with \n then MATLAB will not automatically add a newline at the end: the file will just suddenly end. The sudden ending is not a problem for the file systems, because on all file systems that MATLAB has been implemented on for rather some time, the file system automatically keeps track of the length of the data written.

When 'a' is used, any existing file content is not removed during the fopen(). Any new content written, would be written at the end of file, even if fseek() has been done. If the writting into the file does not end with \n then MATLAB will not automatically add a newline at the end: the file will just suddenly end. The sudden ending is not a problem for the file systems, because on all file systems that MATLAB has been implemented on for rather some time, the file system automatically keeps track of the length of the data written.

When 'r+' is used, any existing file content is not removed during fopen(). Any new content written, would be written at the "current position", which would start out being at the beginning of the file, but could be changed with fseek(). If the writing that produces the furthest writing into the file does not end with \n then MATLAB will not automatically add a newline at the end: the file will just suddenly end. The sudden ending is not a problem for the file systems, because on all file systems that MATLAB has been implemented on for rather some time, the file system automatically keeps track of the length of the data written.

When 'w+' is used, the effect for writing is the same as if 'w' had been used. However, using 'w+' may have effects on the ability to read from the file.

When 'a+' is used, the effect for writing is the same as if 'a' had been used. However, using 'a+' may have effects on the ability to read from the file.

The effects that any of these have on newlines is "NONE".

It is not uncommon for people to assume that if they write something to a file, leaving off a final \n, and then close the file and open it in 'a' mode, that anything new they add will be on a new line after what was written before -- an assumption that the file automatically ends with a newline because nearly all editors show the final line just like the other lines, as if it ended in newline like the other lines do. However this is a mistaken notion: no final \n is automatically added, and any appending to the file will pick up right where the file left off, adding to the end of that line.

Also, it is common for people to want to use dlmwrite() with -append mode to add more data on the end of the same line. That does not work, because dlmwrite() happens to always end the output with \n, and dlmwrite()'s append mode does not "back up" to before the newline: it appends after all existing content in the file, which will be after the \n if you happened to have used dlmwrite() to write the content.