Theroy.md

Python Programming Concepts (Theory)

1️⃣ Introduction to Python

Python is a high-level, interpreted programming language known for its simplicity and readability. It supports multiple programming paradigms, including procedural, object-oriented, and functional programming.

2️⃣ Basic Data Types & Operations

• Integers (int): Whole numbers (e.g., 5, -10)
• Floats (float): Decimal numbers (e.g., 3.14, -2.5)
• Strings (str): Sequence of characters (e.g., 'hello', "Python")
• Booleans (bool): True or False
• Lists (list): Ordered, mutable collections (e.g., [1, 2, 3])
• Tuples (tuple): Ordered, immutable collections (e.g., (1, 2, 3))
• Sets (set): Unordered, unique elements (e.g., {1, 2, 3})
• Dictionaries (dict): Key-value pairs (e.g., {"name": "Alice", "age": 25})

3️⃣ Control Flow Statements

Conditional Statements

if condition:
    # Code block executes if condition is True
elif another_condition:
    # Code block executes if the second condition is True
else:
    # Executes if none of the above conditions are True

Loops

• For Loop: Iterates over a sequence (list, tuple, string, etc.).

  for i in range(5):
      print(i)
• While Loop: Repeats as long as the condition is True.

  i = 0
  while i < 5:
      print(i)
      i += 1

4️⃣ Functions

Functions are reusable blocks of code that perform a specific task.

def greet(name):
    return f"Hello, {name}!"
print(greet("Alice"))

5️⃣ Exception Handling

Exception handling prevents runtime errors from crashing a program.

try:
    result = 10 / 0  # This will raise a ZeroDivisionError
except ZeroDivisionError:
    print("Cannot divide by zero!")
finally:
    print("Execution completed.")

6️⃣ Object-Oriented Programming (OOP)

Classes & Objects

class Car:
    def __init__(self, brand, model):
        self.brand = brand
        self.model = model
    def show_details(self):
        return f"Car: {self.brand} {self.model}"
car1 = Car("Toyota", "Camry")
print(car1.show_details())

Inheritance

Inheritance allows a class to inherit properties and methods from another class.

class Animal:
    def speak(self):
        print("Animal speaks")

class Dog(Animal):
    def speak(self):
        print("Dog barks")

d = Dog()
d.speak()  # Outputs: Dog barks

Method Overriding

When a child class has a method with the same name as a parent class but a different implementation.

7️⃣ File Handling

Writing to a File

with open("data.txt", "w") as file:
    file.write("This is a test file.")

Reading from a File

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

8️⃣ Custom Exceptions

You can define your own exceptions by inheriting from the Exception class.

class NegativeValueError(Exception):
    def __init__(self, message="Value cannot be negative"):
        super().__init__(message)

try:
    value = int(input("Enter a number: "))
    if value < 0:
        raise NegativeValueError()
except NegativeValueError as e:
    print(f"Error: {e}")

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