大约有 45,000 项符合查询结果（耗时：0.0918秒） [XML]
How to add property to a class dynamically?
... a property to a class dynamically. But that's the catch: you have to add it to the class.
>>> class Foo(object):
... pass
...
>>> foo = Foo()
>>> foo.a = 3
>>> Foo.b = property(lambda self: self.a + 1)
>>> foo.b
4
A property is actually a simple...
How to print to console in pytest?
I'm trying to use TDD (test-driven development) with pytest .
pytest will not print to the console when I use print .
...
How to import classes defined in __init__.py
...
'lib/'s parent directory must be in sys.path.
Your 'lib/__init__.py' might look like this:
from . import settings # or just 'import settings' on old Python versions
class Helper(object):
pass
Then the following example should work:
from lib.settings import Values
from lib i...
What is the purpose of Flask's context stacks?
I've been using the request/application context for some time without fully understanding how it works or why it was designed the way it was. What is the purpose of the "stack" when it comes to the request or application context? Are these two separate stacks, or are they both part of one stack? Is ...
How do I initialize the base (super) class?
... invoke their base class through super(), e.g.
class X(object):
def __init__(self, x):
pass
def doit(self, bar):
pass
class Y(X):
def __init__(self):
super(Y, self).__init__(123)
def doit(self, foo):
return super(Y, self).doit(foo)
Because python knows about old- and ne...
How to make a class JSON serializable
...out the expected output? For example, will this do?
>>> f = FileItem("/foo/bar")
>>> magic(f)
'{"fname": "/foo/bar"}'
In that case you can merely call json.dumps(f.__dict__).
If you want more customized output then you will have to subclass JSONEncoder and implement your own ...
How does the @property decorator work in Python?
.... What confuses me is that property can also be used as a decorator, but it only takes arguments when used as a built-in function and not when used as a decorator.
...
Is there a replacement for unistd.h for Windows (Visual C)?
I'm porting a relatively simple console program written for Unix to the Windows platform ( Visual C++ 8.0 ). All the source files include "unistd.h", which doesn't exist. Removing it, I get complaints about misssing prototypes for 'srandom', 'random', and 'getopt'.
I know I can replace the random f...
Proper way to declare custom exceptions in modern Python?
...sed the question, but why not:
class MyException(Exception):
pass
Edit: to override something (or pass extra args), do this:
class ValidationError(Exception):
def __init__(self, message, errors):
# Call the base class constructor with the parameters it needs
super(Valida...
What is the list of supported languages/locales on Android?
...[Amharic (Ethiopia)]
ar_ [Arabic]
ar_001 [Arabic (World)]
ar_AE [Arabic (United Arab Emirates)]
ar_BH [Arabic (Bahrain)]
ar_DJ [Arabic (Djibouti)]
ar_DZ [Arabic (Algeria)]
ar_EG [Arabic (Egypt)]
ar_EH [Arabic (Western Sahara)]
ar_ER [Arabic (Eritrea)]
ar_IL [Arabic (Israel)]
ar_IQ [Arabic (Iraq)]
ar...