Python class variable to call method-CodePudding

so right now I am working on a Tesseract class that has a class variable that calls a function called get_relative_path.

Due to all of the pdf2image and images to string transformation, I save all these files in different folders. But since I don't know the absolute path of all the users I tried to get the relative path depending on the name of the project.

The function I wrote is recursive and does what I expect.

class Tesseract():
   @staticmethod
   def get_relpath_to_folder(folder_name, start_path = '.'):
      for root, dirs, files in os.walk(start_path, topdown=True):
         if folder_name in dirs:
            return os.path.relpath(os.path.join(root,folder_name))
      return Tesseract.get_relpath_to_folder(folder_name, os.path.join('..',start_path ))
   
    rel_path = get_relpath_to_folder(folder_name)

My problem is how do I initialize the class variable with a method.

I tried:

making the method static
making the method class method
putting the class variable above and below the method

So what is the best solution here?

I explicitly want to use class variable because that how I make the rel_path persistent for all objects

CodePudding user response：

The class attribute (not a variable) is evaluated when the class is defined. That is most definitely not what you want to do.

Maybe you want to pass in folder_name to the __init__() method and set the attribute there?

CodePudding user response：

I don't understand all the context, but your question

how do I initialize the class variable with a method.

can be answered: You could use __class__ to refer to a class of an instance.

class SomeClass:
    def set_class_var_from_instance(self, value):
        self.__class__.class_var = value


some_instance = SomeClass()
another_instance = SomeClass()
some_instance.set_class_var_from_instance(1)
assert another_instance.class_var == 1
assert SomeClass.class_var == 1

Another option is to use a @classmethod on the class and set it on the class:

class SomeClass:
    @classmethod
    def set_class_var(cls, value):
         cls.class_var = value

SomeClass.set_class_var(1)
some_instance = SomeClass()
assert some_instance.class_var == 1