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Elegant ways to support equivalence (“equality”) in Python classes
... and != operators. In Python, this is made possible by implementing the __eq__ and __ne__ special methods, respectively. The easiest way I've found to do this is the following method:
...
What is the difference between __init__ and __call__?
I want to know the difference between __init__ and __call__ methods.
13 Answers
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In Python, how do I determine if an object is iterable?
...'ve lately started to get more and more annoyed by objects which only have __getitem__ being considered iterable. There are valid reasons to have __getitem__ in a non-iterable object and with them the above code doesn't work well. As a real life example we can use Faker. The above code reports it be...
What does if __name__ == “__main__”: do?
Given the following code, what does the if __name__ == "__main__": do?
33 Answers
33...
Why is the order in dictionaries and sets arbitrary?
...ash tables, so there's still some liberty). The fact that dictionaries use __hash__ and __eq__ (and nothing else) is practically a language guarantee, not an implementation detail.
– user395760
Mar 18 '13 at 15:16
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How to “perfectly” override a dict?
...bitrary key-altering
function before accessing the keys"""
def __init__(self, *args, **kwargs):
self.store = dict()
self.update(dict(*args, **kwargs)) # use the free update to set keys
def __getitem__(self, key):
return self.store[self.__keytransform__(key)]...
KIO4_Gradient 拓展:布局中的颜色渐变 - App Inventor 2 中文网 - 清泛IT...
http://kio4.com/appinventor/287_extension_gradiente_color.htm
- 让我们看一下在布局中制作颜色渐变的扩展。- 我们放置一个布局,然后在该扩展的块中插入该布局的名称,放置一个包含所需颜色的列表,以及一个从 1 到 8 的数字,用于表示...
Why is __init__() always called after __new__()?
...
Use __new__ when you need to control
the creation of a new instance.
Use
__init__ when you need to control initialization of a new instance.
__new__ is the first step of instance creation. It's called first, and i...
Python read-only property
...he new-style classes.
Example:
>>> class A(object):
... def __init__(self, a):
... self._a = a
...
... @property
... def a(self):
... return self._a
...
>>> a = A('test')
>>> a.a
'test'
>>> a.a = 'pleh'
Traceback (most recent call la...