To call method of Class1 in method of Class2 if instances of classes are created in main function

Question

I have 2 classes:

class ClassOne:
    def __init__(self, file_name):
        self.file_name = file_name
        self.dict = {}

    def load(self):
        #reads from file and parse into dictionary self.dict
       


    def regions(self):
        return list(self.dict.keys()) #returns a list of keys of the dictionary dict

and

class ClassTwo:
    def __init__(self, file_name):
        self.file_name = file_name
        self.dict = {}

    def load(self):
        regions = ClassOne.regions(self)#The issue is here

The load() method does similar things in both classes: open file csv, read from file and parse data into dictionary dict. The only difference that method load() of ClassTwo must call method regions() of the class ClassOne Also, I have main function where I create objects :

def main():

    class_one_object = ClassOne("file1.csv")
    class_one_object.load ():

    class_two_object = ClassTwo("file2.csv")
    class_two_object.load ():
   

if __name__ == "__main__":
    main()

The problem is that I get empty list here: regions = ClassOne.regions(self) because I call ClassOne.regions() with self of ClassTwo, but I need to pass self of ClassOne there somehow.

Also, if I create class_one_object, class_two_object without main, everything works, but I need to use main. Could you help me with the issue, please? I would appreciate any help. Thanks.

Answer 1

Inheritance allows you to do what you want without any copy-pasting or static methods. You create a very detailed ClassOne then inherit it in ClassTwo so that you can access load and regions from there.

Notice the use of super() that gives you a handle to ClassOne while being inside ClassTwo, which allows you to use ClassOne.load.

class ClassOne:
    def __init__(self, file_name):
        self.file_name = file_name
        self.dict = {}

    def load(self):
        print(f"Loading {self.file_name}")
        pass # Do something here.

    def regions(self):
        return list(self.dict.keys()) 


class ClassTwo(ClassOne):
    def load(self):
        super().load() # <---
        self.regions()
        

c1 = ClassOne("file1.csv")
c1.load()
# >>> Loading file1.csv

c2 = ClassTwo("file2.csv")
c2.load()
# >>> Loading file2.csv

Answer 2

OK, tried to understand your question.

my inputs, file1.csv:

a,1,2,3
b,4,5,6

and file2.csv

c,7,8,9
d,10,11,12

my code :

import csv


class ClassOne:
    def __init__(self, file_name):
        self.file_name = file_name
        self.dict = {}

    def load(self):
        #reads from file and parse into dictionary self.dict
        with open(self.file_name, newline='') as csvfile:
            spamreader = csv.reader(csvfile, delimiter=',')
            for row in spamreader:
                    print(' '.join(row))
                    self.dict[row[0]] = row[1:]

    @staticmethod ## works with this line commented out or not
    def regions(self):
        return list(self.dict.keys()) #returns a list of keys of the dictionary dict


class ClassTwo:
    def __init__(self, file_name):
        self.file_name = file_name
        self.dict = {}

    def load(self):
        print('****')
        #reads from file and parse into dictionary self.dict
        with open(self.file_name, newline='') as csvfile:
            spamreader = csv.reader(csvfile, delimiter=',')
            for row in spamreader:
                    print(' '.join(row))
                    self.dict[row[0]] = row[1:]
        regions = ClassOne.regions(self)#The issue is here
        print('\nregions', regions)


def main():

    class_one_object = ClassOne("file1.csv")
    class_one_object.load()

    class_two_object = ClassTwo("file2.csv")
    class_two_object.load()
   

if __name__ == "__main__":
    main()

output:

a 1 2 3
b 4 5 6
****
c 7 8 9
d 10 11 12

regions ['c', 'd']

but I dont get any error, please let me know what I am doing wrong