How can I convert a string to a text file

function [output_text] = censor(file)
%This function takes a file text, searches for a four-letter word, and
%replaces the characters with asterisks. 

txt = importdata(file);
a = char(txt);                                   % arbitary variable names while transforming into the preferred string format
s = size(a);
file_text = [];
words = [];
indeces = [];
W = []
for i = 1:s(1)
    file_text = [file_text a(i,:)];              %takes all of the lines and concatenates them horizontally. 
end
for i = 1:length(file_text)                      %replaces all punctuation with spaces. 
    if isletter(file_text(i)) == 1
        words = [words file_text(i)];
    else words = [words  ' '];
    end
end

for i = 1:length(words)                          %this for loop locates the indeces of 
    if isletter(words(i)) == 1                   %the characters within the four letter words
        W = [W words(i)]
    else
        if length(W) == 4 
            indeces = [indeces i-4 i-3 i-2 i-1]; %iterating variable that records the indeces
            W = [];
        else
            W = [];
        end
    end
end
file_text(indeces) = '*';                         %inputs the recorded indeces into the string of words
output_text = char(file_text);                          %and assigns them to be asterisks
out = [file(1:end-4) '_censored.txt'];
save(out,'output_text')
end

Answer 1

[Stephen23]

You can read about all file import and export functions here:

https://www.mathworks.com/help/matlab/data-import-and-export.html

In particular look at the low-level functions:

https://www.mathworks.com/help/matlab/low-level-file-i-o.html

and try this:

 fid = fopen(out,'wt');
 fprintf(fid,'%s',output_text);
 fclose(fid);