How can I overwrite a variable saved in a script that I have to loop with a different value?

Try to make that simple:

a = [10 20 30 40];
for i = 1:4
    run('blabla.m')     % but inside the script: a = 18
end

Is possible to force the variable 'a' to be equal at a(i) ?

Answer 1

[James Tursa]

Edit the script file blabla.m, and comment out the a = 18 line:

% a = 18;

Also, make sure the script file blabla.m does not clear variables.

Then in your driver code:

A = [10 20 30 40];
for i = 1:4
    a = A(i);
    run('blabla.m')
end

You might also consider turning the blabla.m script file into a function so that you could just pass in the A(i) value directly as an argument.

[Adriano Filippo Inno]

thanks James, but I want to do it w/o modifying the script 'blabla.m'.

In my real case that script is so big and it launches lots of other scripts and functions inside.

I want to know if is possible use run or another Matlab function changing a value inside the ran script.

[James Tursa]

No. If the script file sets "a = 18" directly, then it will override anything you do to try and set it to something else ahead of time. The remedy is to modify the script file (or the functions it calls that use "a") in some way.

If, however, you are willing to set breakpoints in your script file after the "a = 18" line, then you could manually set "a" to something else when the script file pauses in the debugger. But I would imagine that would be a pain to do every time you ran the script file.

[Stephen23]

@Adriano Filippo Inno: this is why we advise beginner to write functions rather than scripts. Then they end up wasting less time trying to create work-arounds for pointless problems like that one you have now. Expert MATLAB users do not write scripts with hard-coded values that call lots of other scripts, instead they write functions that encapsulate some functionality and don't waste their time like you are now.