functools学习记录

装饰器demo

def wrapper(func):
	print('装饰器工作了')
	def inner(*args,**kwargs):
		return func(*args,**kwargs)
	return inner

@wrapper
def index():
	print('index')

@wrapper
def order():
	print('order')

print(index.__name__)
print(order.__name__)

# 结果
装饰器工作了
装饰器工作了
inner
inner

functools.wraps

import functools

def wrapper(func):
	print('装饰器工作了')
	@functools.wraps(func)  # 能够保留被装饰函数的元信息
	def inner(*args,**kwargs):
		return func(*args,**kwargs)
	return inner

@wrapper
def index():
	print('index')

@wrapper
def order():
	print('order')

print(index.__name__)
print(order.__name__)

# 结果
装饰器工作了
装饰器工作了
index
order

functools.partial

偏函数：对函数进行封装，执行的时候自动传参数。

from functools import partial

def func(a,b,c):
    return a+b+c

f1 = partial(func,1)
v = f1(2,3)
print(v)   # 6

偏函数应用

from functools import partial

class RequestContext():
    def __init__(self):
        self.request = '__request__'
        self.session = '__session__'

obj = RequestContext()

def get_data(name):
    if hasattr(obj,name):
        return getattr(obj,name)
    else:
        return None

request_proxy = partial(get_data,'request')
session_proxy = partial(get_data,'session')
request = request_proxy()
session = session_proxy()

print(request)
print(session)