Previous: Duck Typing

When you have just a few classes or constructor functions and their prototypes, hundreds of lines of object-oriented code are easy to organize and maintain. However, as the number of object-oriented blueprints start to increase, it is necessary to follow some rules to organize the code and make it easy to maintain.

• Import Class Object from one file to another

The first and the most straightforward way. A Class Object from one Python file can be imported to another one for usage.

Python File Account.py

# Class Test Account

class Account:
    def __init__(self, number=0.0, balance=0.0, account_type=""):
        print("Account Created")
        self.number = number
        self.balance = balance
        self.account_type = account_type

    def get_number(self):
        return self.number

    def get_balance(self):
        return self.balance

    def get_type(self):
        return self.account_type

    def to_string(self):  # Display the information as String
        print(f"Account[Number = {str(self.number)}, Balance = {str(self.balance)}, "
              f"AccountType = {self.account_type}]")

    def credit(self, amount):  # Add amount to balance
        self.balance = self.balance + amount

    def debit(self, amount):  # Subtract amount to balance
        if self.balance < amount:
            raise ValueError("Cannot subtract the balance to the given amount, "
                             "or Amount Exceeded")
        self.balance = self.balance - amount

    def transfer_to(self, amount, to_account):
        if self.balance < amount:
            raise ValueError("Cannot transfer the given amount from the balance, "
                             "or Amount Exceeded")
        # Transfer from Account to Account
        self.balance = self.balance - amount
        to_account.balance = to_account.balance + amount

Import Class Account to another python file: TestAccount.py

# Import Account
from Account import Account

def main():
    balance1 = float(input("Enter balance for Account 1: "))
    balance2 = float(input("Enter balance for Account 2: "))
    account1 = Account(11, balance1, "USD")
    account2 = Account(12, balance2, "USD")
    # Add 100$ to account1, and 50$ to account2
    account1.credit(100)
    account2.debit(50)
    account1.transfer_to(70, account2)
    print("=================Account1=================")
    print(f"+ Number: {account1.get_number()}")
    print(f"+ Balance: {account1.get_balance()}")
    print(f"+ Account Type: {account1.get_type()}")
    print("==========================================")
    print()
    print("=================Account2=================")
    print(f"+ Number: {account2.get_number()}")
    print(f"+ Balance: {account2.get_balance()}")
    print(f"+ Account Type: {account2.get_type()}")
    print("==========================================")

if __name__ == '__main__':
    main()

• Organize Folders and Subfolders

Each programming language provides different elements and resources to generate object-oriented code. In addition, each programming language provides its own mechanisms that allow you to organize and group different object-oriented elements. Thus, it is necessary to define rules for each of the programming languages.

Imagine that we have to create and furnish house floor plans with a drawing software that allows you to load objects from files.

We have a huge amount of objects to compose our floor plan, such as entry doors, interior doors, square rooms, interior walls, windows, spiral stairs, straight stairs, and kitchen islands.

If we use a single folder in our file system to save all the object files, it will take us a huge amount of time to select the desired object each time we have to add an object to our floor plan.

Organize our objects in the following five folders:

• Build
• Furnish