Python中Functools模块的高级操作详解

import functools

from functools import partial

def add(x, y):
    return x + y

# 使用functools.partial进行柯里化
add_five = partial(add, 5)

# 调用柯里化后的函数
result = add_five(10)  # 结果为15

import functools

def my_decorator(func):
    @functools.wraps(func)
    def wrapper(*args, **kwargs):
        """This is the wrapper function."""
        print("Something is happening before the function is called.")
        result = func(*args, **kwargs)
        print("Something is happening after the function is called.")
        return result
    return wrapper

@my_decorator
def say_hello():
    """This is the say_hello function."""
    print("Hello!")

# 使用functools.wraps装饰后，函数元信息不会丢失
print(say_hello.__name__)  # 输出'say_hello'，而不是'wrapper'
print(say_hello.__doc__)   # 输出'This is the say_hello function.'，而不是'This is the wrapper function.'

import functools

@functools.lru_cache(maxsize=None)
def fibonacci(n):
    if n < 2:
        return n
    return fibonacci(n-1) + fibonacci(n-2)

# 第一次计算fibonacci(30)时会耗时，但后续调用会立即返回缓存的结果
result = fibonacci(30)  # 第一次计算
result = fibonacci(30)  # 立即返回缓存的结果

import functools

# 使用functools.reduce计算阶乘
factorial = functools.reduce(lambda x, y: x * y, range(1, 6))

# 输出120，即5的阶乘
print(factorial)

import functools

# 使用functools.filterfalse筛选出奇数
is_even = lambda x: x % 2 == 0
even_numbers = list(functools.filterfalse(is_even, range(10)))

# 输出[1, 3, 5, 7, 9]，即奇数
print(even_numbers)

import functools

# 自定义比较函数，按长度排序
def compare_length(s1, s2):
    return len(s1) - len(s2)

words = ["apple", "banana", "cherry", "date"]
sorted_words = sorted(words, key=functools.cmp_to_key(compare_length))

# 输出按长度排序的单词列表
print(sorted_words)

import functools

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

    def __eq__(self, other):
        return self.age == other.age

    def __lt__(self, other):
        return self.age < other.age

# 创建两个Person对象
person1 = Person("Alice", 30)
person2 = Person("Bob", 25)

# 使用比较操作符进行对象比较
print(person1 < person2)  # 输出False
print(person1 > person2)  # 输出True

import functools

class MyMath:
    def __init__(self, base):
        self.base = base

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

    # 使用functools.partialmethod创建power_2方法
    power_2 = functools.partialmethod(power, exponent=2)

# 创建MyMath对象
math_obj = MyMath(3)

# 调用部分方法power_2
result = math_obj.power_2()
print(result)  # 输出9