MATLAB: How can MATLAB find and replace a word in a text that contains multiple lines

MATLABtext filetextscan

E.g. if there is a text file with 57 lines and I want a small change of a word in line 54.

Best Answer

You forgot to attach the file. So use fgetl() until you read line 57, then use strrep() on that line.
% Have user browse for a file, from a specified "starting folder."
% For convenience in browsing, set a starting folder from which to browse.
startingFolder = 'C:\Program Files\MATLAB';
if ~exist(startingFolder, 'dir')
  % If that folder doesn't exist, just start in the current folder.
  startingFolder = pwd;
end
% Get the name of the file that the user wants to use.
defaultFileName = fullfile(startingFolder, '*.*');
[baseFileName, folder] = uigetfile(defaultFileName, 'Select a file');
if baseFileName == 0
  % User clicked the Cancel button.
  return;
end
fullFileName = fullfile(folder, baseFileName)
% Open the file.
fileID = fopen(fullFileName, 'rt');
% Read the first line of the file.
textLine = fgetl(fileID);
numLinesRead = 1;
while ischar(textLine)
  % Read the remaining lines of the file.
  fprintf('%s\n', textLine);
  % Read the next line.
  textLine = fgetl(fileID);
  numLinesRead = numLinesRead + 1;
  if numLinesRead == 57
    % Use strrep() on textLine
    changedLine = strrep(textLine, oldText, newText);
    % Then do something with changedLine.
  end
end
% All done reading all lines, so close the file.
fclose(fileID);
Related Question