# Importing libraries import math import os import sys import random import re import json # Defining constants PI = 3.141592653589793 EULER = 2.718281828459045 # Function definitions def greet_user(name): """Prints a greeting for the user.""" print(f"Hello, {name}! Welcome to Python programming.") def calculate_area_of_circle(radius): """Returns the area of a circle.""" return PI * radius ** 2 def is_prime(number): """Checks if a number is a prime.""" if number < 2: return False for i in range(2, int(math.sqrt(number)) + 1): if number % i == 0: return False return True # Using lambda functions square = lambda x: x ** 2 cube = lambda x: x ** 3 # Working with lists, dictionaries, and sets fruits = ["apple", "banana", "cherry", "date"] prices = {"apple": 1.2, "banana": 0.8, "cherry": 2.5, "date": 3.0} fruit_set = set(fruits) # List comprehensions even_numbers = [x for x in range(1, 21) if x % 2 == 0] prime_numbers = [x for x in range(1, 21) if is_prime(x)] # Dictionary comprehensions squared_numbers = {x: x ** 2 for x in range(1, 11)} cubed_numbers = {x: x ** 3 for x in range(1, 11)} # Exception handling try: result = 10 / 0 except ZeroDivisionError as e: print(f"Error: {e}") finally: print("Execution completed.") # File operations with open("example.txt", "w") as file: file.write("This is a sample text file.\n") file.write("It contains multiple lines of text.\n") # Reading files with open("example.txt", "r") as file: content = file.readlines() for line in content: print(line.strip()) # JSON operations data = {"name": "Alice", "age": 25, "city": "Wonderland"} json_data = json.dumps(data) parsed_data = json.loads(json_data) # Regular expressions pattern = r"[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}" email = "[email protected]" if re.match(pattern, email): print(f"Valid email: {email}") # Random numbers random_number = random.randint(1, 100) print(f"Random number: {random_number}") # Classes and objects class Animal: def __init__(self, name, species): self.name = name self.species = species def make_sound(self): return "Some generic sound" class Dog(Animal): def __init__(self, name, breed): super().__init__(name, "Dog") self.breed = breed def make_sound(self): return "Woof!" dog = Dog("Buddy", "Golden Retriever") print(dog.make_sound()) # Decorators def my_decorator(func): def wrapper(*args, **kwargs): print("Before the function call") result = func(*args, **kwargs) print("After the function call") return result return wrapper @my_decorator def say_hello(): print("Hello!") say_hello() # Context managers class MyContextManager: def __enter__(self): print("Entering context") return self def __exit__(self, exc_type, exc_value, traceback): print("Exiting context") with MyContextManager() as cm: print("Inside context") # Iterators and generators class Counter: def __init__(self, start, end): self.current = start self.end = end def __iter__(self): return self def __next__(self): if self.current > self.end: raise StopIteration self.current += 1 return self.current - 1 counter = Counter(1, 10) for num in counter: print(num) def my_generator(): for i in range(5): yield i * 2 gen = my_generator() for value in gen: print(value)