# Variables (dynamically typed)
x = 5
name = "John"
is_active = True

name = "Alice"
age = 25
print(f"Hello, {name}. You are {age} years old")
print("Hello, {}. You are {} years old".format(name, age))

if age >= 18:
    print("Adult")
elif age >= 13:
    print("Teenager")
else:
    print("Child")

fruits = ["apple", "banana", "cherry"]
fruits.append("orange")
fruits[0]  # "apple"
fruits[-1]  # "orange" (last item)
fruits[1:3]  # ["banana", "cherry"] (slice)

person = {"name": "John", "age": 30}
person["city"] = "New York"
person.get("name")  # "John"
person.keys()  # dict_keys(['name', 'age', 'city'])

unique_nums = {1, 2, 3, 3, 4}  # {1, 2, 3, 4}
unique_nums.add(5)
unique_nums.remove(1)

coordinates = (10, 20)
x, y = coordinates  # Unpacking
immutable = (1, 2, 3)  # Cannot be modified

squares = [x**2 for x in range(10)]
# [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

even_squares = [x**2 for x in range(10) if x % 2 == 0]
# [0, 4, 16, 36, 64]

square_dict = {x: x**2 for x in range(5)}
# {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

def greet(name, greeting="Hello"):
    return f"{greeting}, {name}!"

greet("Alice")  # "Hello, Alice!"
greet("Bob", "Hi")  # "Hi, Bob!"

square = lambda x: x**2
numbers = [1, 2, 3, 4]
squared = list(map(square, numbers))  # [1, 4, 9, 16]

def uppercase_decorator(func):
    def wrapper(*args, **kwargs):
        result = func(*args, **kwargs)
        return result.upper()
    return wrapper

@uppercase_decorator
def greet(name):
    return f"hello, {name}"

greet("alice")  # "HELLO, ALICE"

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def greet(self):
        return f"Hi, I'm {self.name}"

person = Person("John", 30)
print(person.greet())  # "Hi, I'm John"

class Student(Person):
    def __init__(self, name, age, student_id):
        super().__init__(name, age)
        self.student_id = student_id

    def study(self):
        return f"{self.name} is studying"