MATLAB: Replacing multiple lines with multiple lines in ascii file

MATLABmultiple linesreplace string

Hi
I would like to make a routine that can replace multiple lines with other multiple lines in a ascii file. This could for example be to replace 7 lines with 4 lines. I can not do it one line at the time because the single lines of the 7 lines are present other places in the file than in the 7 lines.
For single line replacement I have used
fin = fopen('in.txt','r');
fout = fopen('out.txt', 'w+');
while ~feof(fin)
  s = fgetl(fin);
  s = strrep(s, 'old string', 'newstring');
  fprintf(fout,'%s\n',s);
end
fclose(fin);
fclose(fout);
But I can't figure out an easy way to convert this to handle multiple lines replacement.
Do you have any ideas?
Thanks in advance.
Regards Brian.

Best Answer

Can you read the whole file in and then just replace the strings?
wholeFile = fileread('myFile.txt');
newStr = 'This is the replacement for line 2 and 3';
oldStr = ['This is line 2' char(13) char(10) 'This is line 3'];
newFileData = strrep(wholeFile,oldStr,newStr);
fileID = fopen('newFile.txt','w')
fprintf(fileID,'%s',newFileData);
fclose(fileID)
Note that char(10) and char(13) are just line breaks and carriage returns.
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