MATLAB Answers


To substitute a string in matlab script (.m) file using MATLAB.

Asked by Priya
on 18 Jun 2013

I have a script file (.m) file.

I would like to substitute " dist < 6 dist == 6 " in my matlab code file with "dist < 7 dist == 7" and dist < 8 dist == 8 and so on and save each modified script file as a separate .m file.

  1 Comment

Jan Simon
on 18 Jun 2013

What is the your question?

Did you see that the bars disappear in the forum, because they are used as inline code environment?


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1 Answer

Answer by Jan Simon
on 18 Jun 2013
Edited by Jan Simon
on 18 Jun 2013
 Accepted answer

The easiest way would be to replace the constant by a variable and use it as input:

function result = YourOriginalFunc(a)
result = (dist < 6 || dist == 6);
function result = YourNewFunc(a, b)
result = (dist < b || dist == b);

Then there is no need for writing a Matlab program which writes (modifies) Matlab programs. Most of all duplicating a function with changing one tiny detail only is a bad programming practice, because this reduces the maintainability.

But if you have really good reasons:

function result = YourOriginalFunc(a)
constant = 6;
result = (dist < constant || dist == constant);

And the modificator:

Str   = fileread('YourOriginalfunc.m');
CStr  = regexp(Str, '\n', 'split');
index = strncmp(CStr, 'constant =', 10);
for k = 6:10
  CStr{index} = sprintf('constant = %d;', k);
  FID = fopen(sprintf('NewFunc%d.m', k));
  fprintf(FID, '%s\n', CStr{:});

Btw., dist <= constant is faster than comparing the values twice by < and == .

  1 Comment

on 20 Jun 2013


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