Is there a method to combine some functions into a single .m file?

As the title shows, I wonder in Matlab, is there a method to combine several useful functions into one single .m file so the total codes will be more neat? I found that in matlab there's a special type of file named class file. To use it, suppose I have created a class nemed tools, I need to first create an object using

tool = tools;

Then to call one function I defined such as testadd function, I have to input the object tool too! I must input tool as an input! That is to say, to call the function testadd, I have to call it like

testadd(tool,x,y)

I have to input tool at the same time.

So my question is, how can I only call testadd without inputing the tool object? Or, is there some method to combine some functions into a single .m file?

Answer 1

[Hassaan]

In MATLAB, when you're working with object-oriented programming (OOP), you create classes to encapsulate data and functions that operate on that data. The tools you've mentioned seems to be a class, and testadd seems to be a method of that class. When you call a method on an object, you need to reference the object it acts upon, which is why you need to pass tool as an argument.

However, if you want to call testadd without creating an object, you have a couple of options as far I know:

Static Methods: If testadd does not need to access any properties of the tools class, you could make it a static method. Static methods can be called on the class itself, rather than on a particular instance of the class. Here's how you can define a static method in a class:

classdef tools
    methods(Static)
        function result = testadd(x, y)
            result = x + y;
        end
    end
end

You can call a static method like this:

result = tools.testadd(x, y);

Regular Functions: If the functions you want to combine into a single .m file do not need to be part of a class, you could simply define them as separate functions within one file. Starting from R2016b, MATLAB allows you to define local functions at the end of a script. Here's an example:

function result = testadd(x, y)
    result = x + y;
end

Then, you can call testadd directly without needing to create an object:

result = testadd(x, y);

Nested Functions: If your functions need to share some common data, you could use nested functions within a single script or function file.

function mainFunction()
    % Some code
    result = testadd(x, y);
    
    function result = testadd(a, b)
        result = a + b;
    end
end

Remember, you can only call testadd from within mainFunction in this case.

Note

Choose the method that best fits your needs. If testadd is logically a part of the tools class because it operates on the data encapsulated within objects of that class, it should remain a method. If it's more of a standalone function that doesn't require access to the internal state of a tools object, consider one of the alternatives above.

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[Walter Roberson]

If you combine multiple functions into one .m file, then you can only call those functions from within the .m file (unless you somehow export handles to the functions.)

[Walter Roberson]

It is my understanding that you can call static functions without referring to the class, provided that the class is already loaded into memory. So you could call

result = testadd(x, y);

but only once class tools had been loaded.

[Steven Lord]

It is my understanding that you can call static functions without referring to the class, provided that the class is already loaded into memory.

No. Otherwise, what if two classes in the same directory that each had a Static method named testadd had been loaded into memory at the same time? Which of those two Static methods would be called if you tried to call testadd without a class name?

Perhaps you're thinking of classes in a package directory that have been imported using the import function.

Answer 2

[Image Analyst]

Simply make sure the folder where tools lives is on the search path. Then testadd will find it no problem. No need to pass it in via arguments or mess with classes.

[John D'Errico]

Exactly. While it could be done, it also adds needless complexity, making debugging more difficult. It will also probably slow down your code, perhaps significantly.

Answer 3

[Steven Lord]

As the title shows, I wonder in Matlab, is there a method to combine several useful functions into one single .m file so the total codes will be more neat?

How are you hoping to use these functions? Are you hoping to be able to call some or all of them outside the single program file? Or are you hoping to use them as helpers, calling them only from within other functions in the file?

If the former defining them as Static methods of a class is one option, or having the main function return function handles (or a struct array containing function handles) to the local functions inside is another option.

If the latter, create the functions that you want to use inside the file as local functions.