Problem with fprintf

2012 5 28
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Hi All,
I am having a trouble with fprintf and I would so much appreaciate if you could help me: In the programme on which I am working now, I am tracking the mouse position when the mouse is clicked using get(gca, ‘currentpoint’) and then I save the final position using fprintf. Everything works smoothly when I do not define a particular axis position in the figure window; however when I use set(gca, ‘visible’, ‘off’, ‘position’, ‘[]) command to define a particular axis position, fprintf sometimes writes down a string, either K or á, on the text file, which then gives the obvious error with the dlmread when the file is tried to be read. I wonder what might be the cause of those strings on the text file.
Thank you very much,
inci

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Oleg Komarov
Oleg Komarov 2012-5-28
Post an example that generates the issue.
inci
inci 2012-5-28
Thanks but my code is pretty long and complicated (and needs some jpeg files already saved in the directory to run) and everything's dependent on everything so I do not know how can I simplify to put it here for a quick look. I would so much appreaciate some general comments on why fprintf might be writing random strings on the number file, though, if possible?
Oleg Komarov
Oleg Komarov 2012-5-28
We don't even know the syntax you're using for fprintf!
Summarizing a problem is part of being a good programmer. Not being able to do so, means you don't have all the relevant aspects under control. It's not a critic, it's a state that we've all been through. You can try to deal it by yourself or you can ask for help (and I would always encourage the latter) but it should be done properly.
A wild guess:
>> fprintf('%s\n','224')
224
>> fprintf('%s\n',224)
à
inci
inci 2012-5-28
Thanks... My syntax is:
mouse = get(gca,'currentpoint');
A=mouse(1,1); B=mouse(1,2);
save x_center4.txt A -ascii;
save y_center4.txt B -ascii;
A=load('C:\MATLAB6p5\work\x_center4.txt');
B=load('C:\MATLAB6p5\work\y_center4.txt');
fid=fopen('grand_xcenter4.txt','a');
fid2=fopen('grand_ycenter4.txt', 'a'); fprintf(fid,'%s %d\n',A);
fprintf(fid2,'%s %d\n',B); fclose(fid); fclose(fid2);
I guess your suggestion could well be the reason. I am trying to fix my code.

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回答（1 个）

Oleg Komarov
Oleg Komarov 2012-5-28

0 个投票

Transpose A and B:
fprintf(fid,'%s %d\n',A');
fprintf(fid,'%s %d\n',B');
As I understand, you saved two columns, respectively of strings and of numbers. However, fprintf() will process A and B along the first dimension (rows) and will switch to the second one only once the first is over.
To be more clear, I think you expect that frpintf will take a string, than a number, then will go to row 2 and repeat the same, but the default behaviour is to go down till the end THEN switch to the second column, thus you need to transpose.

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inci
inci 2012-5-28
I do not save A and B on the same text file, actually. I open 2 different text files (fid, and fid2) to save mouse position x coordinate and mouse position y coordinate. Both of them are the number files and save double array numbers. But in fact, as you suggested, when I have multiple rows, somehow it creates the problem. First, I read mouse position and save. Then, load it and append it to the fid and fid2 files one after the other on each iteration. I suspect there might be a problem with my fprintf syntax? Many thanks for your time!
inci
inci 2012-5-28
Shall I convert the double arrays (obtained from the load command) to cell before feeding them to fprint?
Oleg Komarov
Oleg Komarov 2012-5-28
fprintf() doesn't accept cell arrays.
As I say above, transpose your A (whatever you called) when it has multiple rows.

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inci
inci
2012-5-28

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