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python_decorator.py
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python_decorator.py
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# _*_ coding: utf-8 _*_
"""
python_decorator.py by xianhu
"""
import functools
# 构建不带参数的装饰器
def logging(func):
@functools.wraps(func)
def decorator(*args, **kwargs):
print("%s called" % func.__name__)
result = func(*args, **kwargs)
print("%s end" % func.__name__)
return result
return decorator
# 使用装饰器
@logging
def test01(a, b):
print("in function test01, a=%s, b=%s" % (a, b))
return 1
# 使用装饰器
@logging
def test02(a, b, c=1):
print("in function test02, a=%s, b=%s, c=%s" % (a, b, c))
return 1
# 构建带参数的装饰器
def params_chack(*types, **kwtypes):
def _outer(func):
@functools.wraps(func)
def _inner(*args, **kwargs):
result = [isinstance(_param, _type) for _param, _type in zip(args, types)]
assert all(result), "params_chack: invalid parameters"
result = [isinstance(kwargs[_param], kwtypes[_param]) for _param in kwargs if _param in kwtypes]
assert all(result), "params_chack: invalid parameters"
return func(*args, **kwargs)
return _inner
return _outer
# 使用装饰器
@params_chack(int, (list, tuple))
def test03(a, b):
print("in function test03, a=%s, b=%s" % (a, b))
return 1
# 使用装饰器
@params_chack(int, str, c=(int, str))
def test04(a, b, c):
print("in function test04, a=%s, b=%s, c=%s" % (a, b, c))
return 1
# 在类的成员方法中使用装饰器
class ATest(object):
@params_chack(object, int, str)
def test(self, a, b):
print("in function test of ATest, a=%s, b=%s" % (a, b))
return 1
# 同时使用多个装饰器
@logging
@params_chack(int, str, (list, tuple))
def test05(a, b, c):
print("in function test05, a=%s, b=%s, c=%s" % (a, b, c))
return 1
# 构建不带参数的装饰器类
class Decorator(object):
def __init__(self, func):
self.func = func
return
def __call__(self, *args, **kwargs):
print("%s called" % self.func.__name__)
result = self.func(*args, **kwargs)
print("%s end" % self.func.__name__)
return result
# 使用装饰器
@Decorator
def test06(a, b, c):
print("in function test06, a=%s, b=%s, c=%s" % (a, b, c))
return 1
# 构建带参数的装饰器类
class ParamCheck(object):
def __init__(self, *types, **kwtypes):
self.types = types
self.kwtypes = kwtypes
return
def __call__(self, func):
@functools.wraps(func)
def _inner(*args, **kwargs):
result = [isinstance(_param, _type) for _param, _type in zip(args, self.types)]
assert all(result), "params_chack: invalid parameters"
result = [isinstance(kwargs[_param], self.kwtypes[_param]) for _param in kwargs if _param in self.kwtypes]
assert all(result), "params_chack: invalid parameters"
return func(*args, **kwargs)
return _inner
# 使用装饰器
@ParamCheck(int, str, (list, tuple))
def test07(a, b, c):
print("in function test06, a=%s, b=%s, c=%s" % (a, b, c))
return 1
# 装饰器实例: 函数缓存
def funccache(func):
cache = {}
@functools.wraps(func)
def _inner(*args):
if args not in cache:
cache[args] = func(*args)
return cache[args]
return _inner
# 使用装饰器
@funccache
def test08(a, b, c):
# 其他复杂或耗时计算
return a + b + c
# 使用Python自带的装饰器 @property
class Person(object):
def __init__(self):
self._name = None
return
def get_name(self):
print("get_name")
return self._name
def set_name(self, name):
print("set_name")
self._name = name
return
name = property(fget=get_name, fset=set_name, doc="person name")
# 使用Python自带的装饰器 @property
class People(object):
def __init__(self):
self._name = None
self._age = None
return
@property
def name(self):
return self._name
@name.setter
def name(self, name):
self._name = name
return
@property
def age(self):
return self._age
@age.setter
def age(self, age):
assert 0 < age < 120
self._age = age
return
# 类静态方法和类方法
class A(object):
var = 1
def func(self):
print(self.var)
return
@staticmethod
def static_func():
print(A.var)
return
@classmethod
def class_func(cls):
print(cls.var)
cls().func()
return