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Intermediate Python Programming Tutorial


Introduction



Welcome to the Intermediate Python Programming tutorial! This tutorial is designed for individuals who have a basic understanding of Python and want to explore more advanced concepts and techniques.


Table of Contents


  1. Object-Oriented Programming (OOP)
  2. File Handling
  3. Error Handling
  4. Working with Modules and Packages

1. Object-Oriented Programming (OOP)

Object-Oriented Programming (OOP) is a programming paradigm that allows you to create objects with properties and behaviors. In Python, you can implement OOP concepts using classes, objects, inheritance, polymorphism, and encapsulation.


Example: Creating a Class and Objects

Let's start by creating a class called `Car` that represents a car object with properties like `make`, `model`, and `year`.


class Car:
    def __init__(self, make, model, year):
        self.make = make
        self.model = model
        self.year = year

# Creating objects of the Car class
car1 = Car("Tesla", "Model 3", 2022)
car2 = Car("Ford", "Mustang", 2021)
  

In the above example, we defined a class `Car` with an `__init__` method, which is a special method used to initialize the object's properties. We then created two objects, `car1` and `car2`, with different property values.


Example: Inheritance and Polymorphism

Inheritance allows us to create a new class that inherits the properties and methods of an existing class. Polymorphism, on the other hand, enables objects of different classes to be used interchangeably based on their shared behaviors.


class ElectricCar(Car):
    def __init__(self, make, model, year, battery_capacity):
        super().__init__(make, model, year)
        self.battery_capacity = battery_capacity

    def display_info(self):
        print(f"This {self.make} {self.model} has a battery capacity of {self.battery_capacity} kWh.")

# Creating an object of the ElectricCar class
electric_car = ElectricCar("Tesla", "Model S", 2022, 100)

# Using polymorphism to call the display_info() method
electric_car.display_info()
  

In this example, we created a subclass `ElectricCar` that inherits from the `Car` class. The subclass has an additional property, `battery_capacity`. We also defined a custom method, `display_info()`, specific to the `ElectricCar` class. The `super()` function is used to call the parent class's `__init__` method. Finally, we created an object of the `ElectricCar` class and called the `display_info()` method, demonstrating polymorphism.


2. File Handling

File handling is an essential skill in Python programming. In this section, we will explore various file operations, including reading from and writing to files, manipulating file paths, and working with file objects.


Example: Reading from a File

Let's read the contents of a file called `data.txt`:


with open("data.txt", "r") as file:
    content = file.read()
    print(content)
  

In the above example, we used the `open()` function to open the file in read mode (`"r"`). We then used the `read()` method to read the entire contents of the file and assigned it to the `content` variable. Finally, we printed the content.


Example: Writing to a File

Let's write some data to a file called `output.txt`:


with open("output.txt", "w") as file:
    file.write("Hello, world!")
  

In the above example, we opened the file in write mode (`"w"`) and used the `write()` method to write the text "Hello, world!" to the file.


3. Error Handling

Error handling is crucial for building robust Python applications. In this section, we will learn about handling exceptions, raising custom exceptions, and using the `try-except-finally` block effectively to gracefully handle errors.


Example: Handling Exceptions

Let's see an example of catching and handling an exception:


try:
    number = int(input("Enter a number: "))
    result = 10 / number
    print("Result:", result)
except ValueError:
    print("Invalid input. Please enter a valid number.")
except ZeroDivisionError:
    print("Cannot divide by zero.")
  

In the above example, we use the `try-except` block to catch specific exceptions. If a `ValueError` occurs (e.g., when the user enters a non-numeric input), the corresponding `except` block is executed. Similarly, if a `ZeroDivisionError` occurs (e.g., when the user enters zero as the input), the respective `except` block is executed.


Example: Raising Custom Exceptions

We can also raise our own exceptions to indicate errors or exceptional situations:


def calculate_square_root(number):
    if number < 0:
        raise ValueError("Cannot calculate square root of a negative number.")
    else:
        return math.sqrt(number)
  

In the above example, if a negative number is passed to the `calculate_square_root()` function, a `ValueError` with a custom message is raised. This allows us to handle specific exceptional situations in our code.


4. Working with Modules and Packages

Python provides a modular approach to organize code using modules and packages. In this section, we will explore how to create modules, import modules, and structure code into packages for better code organization and reusability.


Example: Creating a Module

Let's create a module named `math_operations.py` that contains mathematical operations:


# math_operations.py
def add(a, b):
    return a + b

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

def multiply(a, b):
    return a * b
  

In the above example, we define three functions: `add()`, `subtract()`, and `multiply()`. These functions can be used in other Python programs by importing the `math_operations` module.


Example: Importing and Using a Module

Let's import the `math_operations` module and use its functions:


import math_operations

result = math_operations.add(5, 3)
print("Result:", result)
  

In the above example, we import the `math_operations` module and use its `add()` function to add two numbers. We then print the result.


Conclusion

Congratulations on completing the Intermediate Python Programming tutorial! By covering these advanced topics, you are well-equipped to tackle more complex projects and solve challenging problems using Python.


Remember, practice is key to mastering any programming language. Keep exploring, experimenting, and building projects to solidify your skills and continue your learning journey.

Happy coding!


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