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start to write for a specified location using fprintf

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FileName1='data_file';
result_1=23.9;
FileName2='data_file2';
result_2=21.9;
startingFolder='C:\Program Files\MATLAB';
if ~exist(startingFolder, 'dir')
startingFolder = pwd;
end
defaultFileName=fullfile(startingFolder, '*.txt');
[baseFileName, folder]=uiputfile(defaultFileName, 'Select a file');
if baseFileName == 0
return
end
fullFileName = fullfile(folder, baseFileName); %fullfile=building file
fid = fopen(fullFileName, 'w');
How can I write a text file (starting with line 2) for the results as following:
result_1 result_2
data_file: 23.9 data_file2: 21.9

Accepted Answer

Scott MacKenzie
Scott MacKenzie on 12 Jul 2021
Here's a solution. Make sure you use "r+" when opening the file, otherwise you'll overwrite the first line.
fid = fopen('testdata.txt', 'r+'); % open file for reading and writing
fgetl(fid); % skip over 1st line
fprintf(fid','data_file: %.1f data_file2: %.1f\n', result_1, result_2);
fclose(fid);
  5 Comments
sermet OGUTCU
sermet OGUTCU on 13 Jul 2021
Dear @Walter, thank you very much for the clarification.

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More Answers (1)

Scott MacKenzie
Scott MacKenzie on 12 Jul 2021
fid = fopen('testdata.txt', 'w'); % change, as needed
fprintf(fid, ' result_1 result_2\n');
fprintf(fid','data_file: %.1f data_file2: %.1f\n', result_1, result_2);
fclose(fid);
  5 Comments
Walter Roberson
Walter Roberson on 12 Jul 2021
POSIX requirement.
When a file is opened with update mode ( '+' as the second or third character in the mode argument), both input and output may be performed on the associated stream. However, the application shall ensure that output is not directly followed by input without an intervening call to fflush() or to a file positioning function ( fseek(), fsetpos(), or rewind()), and input is not directly followed by output without an intervening call to a file positioning function, unless the input operation encounters end-of-file.

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