MATLAB: How to define a variable that store its value after closing MATLAB file

globalpersistentstatic

Hi,

I just want to declare a variable that holds its value through the whole file and even after closing it , also to initialize it externally . I tried to use 'persistent' variables but they're locally defined and so I have to initialize it locally , that makes its value initialized each time the function is called. When I define it global to avoid the repeated initialization through the same file , a warning appears 'the variable can apparently be used before it's defined' and an error 'undefined variable'. I need this variable to save txt files that contains the incremented variable value in its name.

Thanks in advance

Best Answer

Thank you very much Jan Simon for your answer and thank u all

but I found a solution for my question , and it works as I want .. I just used a text file to keep the variables that I want them not to lose their values and I used them in my program (using save and load commands) only to be incremented to use them in naming a series of files . I don't know if I explained that well but I just want to close this question .

Related Solutions

MATLAB: What’s a persistent variable???

A persistent variable retains its values between calls to the routine.

For example

function trial
    persistent times_called
    if isempty(times_called); times_called = 0; end  %never called before
    times_called = times_called + 1;
    if mod(times_called,10) == 0
      fprintf('Trial called %d times so far\n', times_called);
    end
    %now do the real work of the routine
    .....
end

The above is just one of many uses.

MATLAB: How can I take a global variable declared in a program, take it in a function, change its value inside the fuction and give it again to the program as global

You don't need to pass global variables anywhere.

You just keep putting

global myVariable

within any scope in which you wish to use it.

That said, it is terrible programming technique to use global variables. Just do something like:

value = doSomething( value );

in your main program with a normal (non-global) variable passed into a function and then passed out again after being updated. There are other techniques too, but that is probably the simplest.

Best Answer

Related Solutions

MATLAB: What’s a persistent variable???

MATLAB: How can I take a global variable declared in a program, take it in a function, change its value inside the fuction and give it again to the program as global

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