a, b = 17, 5

print(a + b)    # 22
print(a - b)    # 12
print(a * b)    # 85
print(a / b)    # 3.4
print(a // b)   # 3  (floor division - rounds down)
print(a % b)    # 2  (remainder)
print(a ** b)   # 1419857  (17 to the power of 5)

# Negative floor division rounds toward negative infinity
print(-17 // 5)   # -4 (not -3!)
print(-17 % 5)    # 3

x, y = 10, 20

print(x == y)   # False
print(x != y)   # True
print(x > y)    # False
print(x < y)    # True
print(x >= 10)  # True
print(x <= 5)   # False

# Chained comparisons (unique to Python!)
age = 25
print(18 <= age <= 65)  # True
print(1 < 2 < 3 < 4)   # True

# String comparison (lexicographic)
print("apple" < "banana")  # True
print("abc" == "abc")      # True

x = 15

# Combining conditions
print(x > 10 and x < 20)   # True
print(x > 20 or x < 10)    # False
print(not (x > 20))         # True

# Short-circuit evaluation
# 'and' stops at first False, 'or' stops at first True
print(False and print("never runs"))  # False (print not executed)
print(True or print("never runs"))    # True (print not executed)

# Practical example
age = 25
has_license = True
if age >= 18 and has_license:
    print("Can drive")

# 'and' returns first falsy value or last value
print(1 and 2 and 3)      # 3 (all truthy, returns last)
print(1 and 0 and 3)      # 0 (first falsy)
print("" and "hello")     # "" (first falsy)

# 'or' returns first truthy value or last value
print(0 or "" or "hello") # "hello" (first truthy)
print(0 or "" or [])      # [] (all falsy, returns last)

# Common pattern: default values
name = "" or "Anonymous"
print(name)  # Anonymous

port = None or 8080
print(port)  # 8080

x = 10
x += 5     # x = 15
x -= 3     # x = 12
x *= 2     # x = 24
x //= 5    # x = 4
x **= 3    # x = 64
print(x)   # 64

# Works with strings too
greeting = "Hello"
greeting += " World"
print(greeting)  # Hello World

# Works with lists
items = [1, 2]
items += [3, 4]
print(items)  # [1, 2, 3, 4]

# Without walrus operator
data = input("Enter data: ")
if len(data) > 10:
    print(f"Too long: {len(data)} characters")

# With walrus operator
if (n := len(input("Enter data: "))) > 10:
    print(f"Too long: {n} characters")

# Useful in while loops
while (line := input("Enter text (q to quit): ")) != "q":
    print(f"You entered: {line}")

# In list comprehensions
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
results = [y for x in numbers if (y := x ** 2) > 25]
print(results)  # [36, 49, 64, 81, 100]

a = [1, 2, 3]
b = [1, 2, 3]
c = a

print(a == b)      # True (same value)
print(a is b)      # False (different objects)
print(a is c)      # True (same object)
print(a is not b)  # True

# Always use 'is' with None
x = None
print(x is None)      # True (correct)
print(x == None)       # True (works but not recommended)

# In strings
print("Py" in "Python")     # True
print("java" in "Python")   # False

# In lists
fruits = ["apple", "banana", "cherry"]
print("banana" in fruits)     # True
print("grape" not in fruits)  # True

# In dictionaries (checks keys by default)
user = {"name": "Alice", "age": 25}
print("name" in user)        # True
print("email" in user)       # False
print("Alice" in user.values())  # True

# In range
print(5 in range(10))   # True
print(15 in range(10))  # False

a = 0b1010  # 10
b = 0b1100  # 12

print(bin(a & b))   # 0b1000 (AND: 8)
print(bin(a | b))   # 0b1110 (OR: 14)
print(bin(a ^ b))   # 0b0110 (XOR: 6)
print(bin(~a))      # -0b1011 (NOT: -11)
print(bin(a << 2))  # 0b101000 (Left shift: 40)
print(bin(a >> 1))  # 0b101 (Right shift: 5)

# Practical: check if number is even/odd
num = 7
print("odd" if num & 1 else "even")  # odd

# Practical: flags
READ    = 0b100  # 4
WRITE   = 0b010  # 2
EXECUTE = 0b001  # 1

permissions = READ | WRITE  # 6 (read + write)
print(bool(permissions & READ))     # True
print(bool(permissions & EXECUTE))  # False

# Precedence matters!
print(2 + 3 * 4)       # 14 (not 20)
print((2 + 3) * 4)     # 20

print(2 ** 3 ** 2)     # 512 (right-associative: 2^(3^2) = 2^9)
print((2 ** 3) ** 2)   # 64

# When in doubt, use parentheses!
result = (a + b) * (c - d) / (e ** f)