Functools Higher-Order Functions

Introduction

Functools provides higher-order functions and operations on callable objects.

LRU Cache

from functools import lru_cache

@lru_cache(maxsize=128)
def fibonacci(n):
    if n < 2:
        return n
    return fibonacci(n-1) + fibonacci(n-2)

# Clear cache
fibonacci.cache_clear()

# Cache info
print(fibonacci.cache_info())
# CacheInfo(hits=0, misses=60, ...)

Partial Functions

from functools import partial

def power(base, exponent):
    return base ** exponent

square = partial(power, exponent=2)
cube = partial(power, exponent=3)

print(square(5))  # 25
print(cube(3))    # 27

Reducing Functions

from functools import reduce

# Reduce to single value
numbers = [1, 2, 3, 4, 5]
result = reduce(lambda x, y: x * y, numbers)
print(result)  # 120

Practice Problems

1. Memoize recursive factorial
2. Create partial function with positional args
3. Use reduce for custom aggregations
4. Implement caching decorator
5. Create function composition with reduce