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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 most efficient/elegant way to parse a flat table into a tree?
...e Pitfalls of Database Programming.
CREATE TABLE ClosureTable (
ancestor_id INT NOT NULL REFERENCES FlatTable(id),
descendant_id INT NOT NULL REFERENCES FlatTable(id),
PRIMARY KEY (ancestor_id, descendant_id)
);
Store all paths in the Closure Table, where there is a direct ancestry from o...
Getting attributes of a class
...gt;> inspect.getmembers(MyClass, lambda a:not(inspect.isroutine(a)))
[('__class__', type),
('__dict__',
<dictproxy {'__dict__': <attribute '__dict__' of 'MyClass' objects>,
'__doc__': None,
'__module__': '__main__',
'__weakref__': <attribute '__weakref__' of 'MyClass' obje...
What is the difference between __init__ and __call__?
I want to know the difference between __init__ and __call__ methods.
13 Answers
...
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
...
How do I implement __getattribute__ without an infinite recursion error?
...n a class, but return all others normally. How do I accomplish this with __getattribute__ ?
6 Answers
...
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)]...
__attribute__ - C/C++ - 清泛网 - 专注C/C++及内核技术
__attribute____attribute__instructionsGNU C的一大特色（却不被初学者所知）就是__attribute__机制。__attribute__可以设置函数属性（Function Attribute）、变量属性（Variabl GNU C的一大特色（却不被初学者所知）就是__attribute__机制。__attribute__可...