Loop through text files, replace consecutive asterisks with 0.00 - matlab

Question

all,
I am writing a matlab program to read in text data and rearrange it. Now I am meeting with a new problem.
When I am writing data out to csv file, there are randomly missing data noted as ******, as shown below causing my program to terminate.
2055 6 17 24.2 29.57 7.02****** 0.99 2.65 2.73 4.09 0.11
Any one can help me with a small program to loop through all the text files in the folder, and replace the consecutive stars, with 0.00? The stars are always in columns 33 to 38, occupying 6 spaces. I want it to be changed to be two spaces followed by 0.00.
Thanks,
James

Answer 1

For a given text file, you can read it into memory, replace the asterisks with the desired text, and then overwrite the original text file:
filename = 'blah.txt'
% Read it into memory
fid = fopen(filename, 'r');
scanned_fields = textscan(fid, '%s', 'Delimiter','\n');
fclose(fid);
% The first (and only) field of textscan will be our cell array of text
lines = scanned_fields{1};
% Replace the asterisks with the desired text
lines = strrep(lines, '******', ' 0.00');
% Overwrite the original file
fid = fopen(filename, 'w');
fprintf(fid, '%s\n', lines{:});
fclose(fid);
To do this for all of the text files in your directory, you can use dir to get a list of files in your current directory that end in ".txt":
files = dir('*.m');
filenames = {files.name};
And then loop over the files:
for ii = 1:length(filenames)
filename = filenames{ii};
% Read it into memory
fid = fopen(filename, 'r');
scanned_fields = textscan(fid, '%s', 'Delimiter','\n');
fclose(fid);
lines = scanned_fields{1};
% Replace the asterisks with the desired text
lines = strrep(lines, '******', ' 0.00');
% Overwrite the original file
fid = fopen(filename, 'w');
fprintf(fid, '%s\n', lines{:});
fclose(fid);
% Go on to the next file
end
And of course, I would recommend creating a backup copy of this directory before running this, just in case something unexpected comes up.