Python’s import statement is a powerful tool that allows us to use code written in one file within another file. This is especially useful when working with class files, as it helps organize and reuse code efficiently. In this beginner-friendly blog post, we will explore the step-by-step process of importing class files into other class files in Python, using code snippets as examples. So let’s dive in!

Step 1: Create the class file To begin with, let’s create a class file called calculator.py that contains a simple Calculator class:

calculator.py

class Calculator:
    def add(self, a, b):
        return a + b
    def subtract(self, a, b):
        return a - b
class Calculator:
    def add(self, a, b):
        return a + b

    def subtract(self, a, b):
        return a - b
class Calculator:
    def add(self, a, b):
        return a + b

    def subtract(self, a, b):
        return a - b

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Step 2: Now, let’s create another class file called main.py that will import the Calculator class from calculator.py and utilize its functionalities:

# main.py
from calculator import Calculator
# main.py

from calculator import Calculator
# main.py

from calculator import Calculator

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Step 2.5 Let’s start using our Calculator class from within our main.py file.

# main.py
# Create an instance of the Calculator class
calc = Calculator()
# main.py
# Create an instance of the Calculator class
calc = Calculator()
# main.py
# Create an instance of the Calculator class
calc = Calculator()

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# main.py
# Use the 'add' method from the Calculator class
result = calc.add(5, 3)
print("Addition result:", result)
# main.py
# Use the 'add' method from the Calculator class
result = calc.add(5, 3)
print("Addition result:", result)
# main.py
# Use the 'add' method from the Calculator class
result = calc.add(5, 3)
print("Addition result:", result)

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# main.py
# Use the 'subtract' method from the Calculator class
result = calc.subtract(5, 3)
print("Subtraction result:", result)
# main.py
# Use the 'subtract' method from the Calculator class
result = calc.subtract(5, 3)
print("Subtraction result:", result)
# main.py
# Use the 'subtract' method from the Calculator class
result = calc.subtract(5, 3)
print("Subtraction result:", result)

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Step 3: Understanding the import statement In the code snippet above, we used the import statement to import the Calculator class from the calculator.py file. This allows us to create an instance of the Calculator class and access its methods.

Step 4: Now, save both the calculator.py and main.py files in the same directory (lib is a common choice here.), and run the main.py file. You should see the following output:

Addition result: 8
Subtraction result: 2
Addition result: 8
Subtraction result: 2
Addition result: 8
Subtraction result: 2

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Congratulations! You have successfully imported class files in Python.

In this beginner’s guide, we explored the step-by-step process of importing class files in Python. We learned how to create a separate class file, import it into another file using the import statement, and utilize the imported class’s methods. This technique is an essential aspect of Python programming, enabling code organization and modularity!

原文链接：Importing Class Files in Python: A Beginner’s Guide