假设有这样一个快速的装饰示例:
def read_a_book():
return "I am reading the book: "
def add_a_book(func):
def wrapper():
return func() + "Python Cookbook"
return wrapper
快跑过来
In [7]: read_a_book = add_a_book(read_a_book)
In [8]: read_a_book()
Out[8]: 'I am reading the book: P
我在试着理解python的装潢师。在我写这段代码之前,我一直以为我能理解装饰师。
def func():
def wrapper(x):
return x()
return wrapper
@func()
def b():
return sum
a = b([1,2,5])
print a # Result: 8 How?
e = b # pass b function to variable e
f = e([3,4,8]) # called function b stored in variable e
print f # Result:
当我尝试在视图上使用自定义装饰器时,出现错误。根据我所能找到的,问题似乎是在修饰的函数上没有使用@wraps,但我这样做了,似乎仍然得到了一个错误,即视图函数映射已经存在。 def logout_required(url="/"):
"""
Redirect a user to a specified location if they are already signed in.
:param url: URL to be redirected to if invalid
:type url: str
:ret
如何将index()传递给名为uppercase()的装饰器函数。我希望从index()传递的值被大写化。
我得到了这个错误:
500 Internal Server Error
The server encountered an unexpected condition which prevented it from fulfilling the request.
Traceback (most recent call last):
File "/home/user/.local/lib/python3.6/site-packages/cherrypy/_cprequest.p
我从这个中了解到,在Python中,装饰符是按照它们在源代码中出现的顺序来应用的。
那么,下面的代码片段将如何表现呢?
@unittest.skip("Something no longer supported")
@skipIf(not something_feature_enabled, "Requires extra crunchy cookies to run")
def test_this():
....
第一个装饰器(注意到下面)要求测试运行程序完全跳过test_this()
@unittest.skip("Something no lo
我在以下类的__init__方法中的flask/helpers.py中添加了一条assert False语句: class locked_cached_property(object):
"""A decorator that converts a function into a lazy property. The
function wrapped is called the first time to retrieve the result
and then that calculated result is used the next
只是玩装饰,并有一个简单的例子,我做了。我以为每次调用方法时,都会将方法名添加到列表中。
python_func_calls = []
def log_func_call(func):
python_func_calls.append(func.__name__)
return func
@log_func_call
def print_a():
print('I am the a function...')
@log_func_call
def print_b():
print('I am the b function..
我开始学习python中的装饰器。我有以下疑问吗?
def add(a):
print 'This is an addition function'
return a
@add
def dollar():
print 'Am i getting the concept ?'
dollar()
这个调用给我的输出是
This is an addition function
Am i getting the concept ?
但是如果我像这样调用函数,我会得到下面的错误
def add(a):
a
print 'This is a
我试图理解@main注释在python中的用法。通过下面的python程序,
def cube(x):
return x * x * x
def run_tests():
printf("Should be 1:", cube(1))
printf("Should be 8:", cube(2))
printf("Should be 27:", cube(3))
@main
def main():
print("Starting")
run_tests()
print(&
我想升级我的python测试工具--它基于Python的单元测试模块--从Python2升级到Python3。然而,unittest.expectedFailure装饰师似乎不再有同样的效果了。特别是,以下代码具有不同的行为,取决于Python版本,尽管规范实际上是相同的:
#!/usr/bin/env python2
#!/usr/bin/env python3
# Switch between the two lines above to get the different outcome
import unittest
class ComparisonTests(unittest.T
我只是试图熟悉Python中的装饰器,但作为该语言的新手,我不明白为什么我会得到以下结果:
我的带有参数的装饰器代码如下:
def decorator_with_argument(fun_name):
def decorator_func(func):
'''decorator function which will provide additional functionality to my original function'''
print("Inside decorator")