List variables in m-file

I would like to rename some variables in an m-file, and would like to automate this process. I have tried using regexprep, but ran into some problems. I noticed a feature in the newest versions of Matlab, where you can automatically rename variables. Is there a command line version of this functionality. Alternatively, what would be the best way of renaming the variables, without having to run the file?

[Cedric]

Do you know the name of these variables a priori, or is it something that has to be detected by the program?

[Etienne Coetzee]

Yes, I have the names, but some variables are for instance N and NN, so I am not sure how to prevent NN from changing when I want to change N to AB for instance. NN will then become ABAB.

Answer 1

[Walter Roberson]

Example of replacing a variable in a string:

S = 'x^2 + 3*x*y + x1/x';
regexprep(S, '(?<![A-Za-z0-9_])x(?![A-Za-z0-9_])', 'YO')

[Cedric]

Is there a reason why you didn't use \w in the look-around? Was it just to make the pattern more explicit for the example?

[Etienne Coetzee]

Hi Walter. That is exactly what I wanted. I have tried it, and it works. Thank you. That has made my day.

[Walter Roberson]

\w would likely be a good idea. I was thinking at the time that it matched a slightly different set of characters than was needed for MATLAB identifiers, but you are right that it is the same.