"""

How to use lambda functions in Python.

1. Lambda function is a one-line function

2. Lambda function is an anonymous function (without function name)

3. How to define a lambda function: lambda arguments: expression (usually use in a mathmatical expression)

"""

from functools import wraps

# 1. Basic -- anoynmous function

def divide_by_zero(func):

@wraps(func)

def wrapper(*args, **kwargs):

y = args[1] if args else kwargs.get("y")

# operation = args[2] if args else kwargs.get("operation")

if y == 0: # suppose the operation is division

raise ZeroDivisionError("Cannot divide by zero.")

return func(*args, **kwargs)

return wrapper

@divide_by_zero

def apply_operations(x, y, operation):

return operation(x, y)

res = apply_operations(1, 5, lambda a, b: a + b)

print(f"res: {res}")

# 2. map(lambda, iter) and sorted(iter, key)

def add_tax_for_salary(salary, tax_rate):

return list(map(lambda s: s * (1 - tax_rate), salary))

salary = [100000, 90000, 80000]

tax_rate = 0.4

print(f"Salary after tax: {add_tax_for_salary(salary=salary, tax_rate=tax_rate)}")

products = [

{'name': 'Laptop', 'price': 1200},

{'name': 'Mouse', 'price': 25},

{'name': 'Keyboard', 'price': 80}

]

# sort by price

sorted_price = sorted(products, key=lambda p: p['price'])

print(f"Sorted by price for products: {sorted_price}")

# sort by length of name, descending

sorted_name_len = sorted(products, key=lambda p: len(p['name']), reverse=True)

print(f"Sorted by name for products: {sorted_name_len}")