How to do a loop in a text file until an empty line is found

Question

Hugo 2020-11-3

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回答： Image Analyst 2020-11-4

Hello,

I would like to open an external text file and do a loop that scans all the lines of the text file until an empty line is found. I know how to code what I would like to do, but I am not sure how I can replace my "For" cycle by a "While" cycle. Could someone help?

I thank you in advance,

Best regards,

Hugo

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Answer 1

Cris LaPierre 2020-11-3

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编辑：Cris LaPierre 2020-11-3

Look at the example on the documentation page for fgetl. Assuming you are doing this in a loop (for or while, doesn't matter), you can use the break command to stop if the result of fgetl is empty.

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Answer 2

Image Analyst 2020-11-4

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在 MATLAB Online 中打开

Try this:

% Open the file for reading in text mode.
fileID = fopen(fullFileName, 'rt');
% Read the first line of the file.
textLine = fgetl(fileID);
lineCounter = 1;
while ischar(textLine)
	% Print out what line we're operating on.
	fprintf('%s\n', textLine);
	% Read the next line.
	textLine = fgetl(fileID);
        if length(textLine) == 0
            break;
        end
	lineCounter = lineCounter + 1;
end
% All done reading all lines, so close the file.
fclose(fileID);

You might also want to look at strtrim() to handle lines that have nothing but spaces on them. Not sure if you want to break on a line that was a space or not.