[英]Issue creating decorator in Python3
谁能让我知道我在犯什么错误。
import time
def f1(f):
a = time.time()
f()
b = time.time()
c = b-a
print("time required is", c)
@f1
def f3(f2):
n = []
for i in range(1000):
n.append(i)
print(sum(n), "for F3")
f2()
@f3
def f4():
n = []
for i in range(1000):
n.append(i)
print(sum(n), "for F4")
f4
o / p:
追溯(最近一次通话):
File "C:/test.py", line 13, in <module>
@f1
File "C:/test.py", line 7, in f1
f()
TypeError: f3() missing 1 required positional argument: 'f2'
Process finished with exit code 1
希望实现以下目标:
def decorator_with_args(decorator_to_enhance):
def decorator_maker(*args, **kwargs):
def decorator_wrapper(func):
return decorator_to_enhance(func, *args, **kwargs)
return decorator_wrapper
return decorator_maker
@decorator_with_args
def装饰的装饰器(func,* args,** kwargs):
def wrapper(function_arg1, function_arg2):
print("Decorated with {0} {1}".format(args, kwargs))
return func(function_arg1, function_arg2)
return wrapper
@decorated_decorator(42,404,1024)
def装饰函数(function_arg1,function_arg2):
print("Hello {0} {1}".format(function_arg1, function_arg2))
装饰函数(“ Universe and”,“ everything”)
虽然您可以在另一个不返回任何可调用对象的单个函数中进行包装和运行,但是请记住,包装后的函数不再可调用。 因此,在对不需要原始对象可重用性的对象进行计时时,当前代码可以正常工作:
import time
def timeit(f):
c = time.time()
_ = f()
c2 = time.time()
print(f"'{f.__name__}' took {c2-c}s")
@timeit
def f2():
return sum(range(1000))
输出(不调用f2
):
'f2' took 8.988380432128906e-05s
但是,如果尝试调用f2
:
_ = f2()
追溯(最近一次调用):TypeError中的文件“”,第1行:'NoneType'对象不可调用
为防止上述错误,请在装饰函数内部创建一个包装器函数:
def timeit(f):
def wrapper(*args, **kwargs):
c = time.time()
_result = f(*args, **kwargs)
c2 = time.time()
print(f"'{f.__name__}' took {c2-c}s")
return _result
return wrapper
@timeit
def f2():
return sum(range(1000))
f2
直到被调用才被计时,触发wrapper
:
print(f2())
输出:
'f2' took 3.981590270996094e-05s
499500
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