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What are the mechanics of short string optimization in libc++?
...
The libc++ basic_string is designed to have a sizeof 3 words on all architectures, where sizeof(word) == sizeof(void*). You have correctly dissected the long/short flag, and the size field in the short form.
what value would __min_cap, ...
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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In which case do you use the JPA @JoinTable annotation?
...ble named Task and add a foreign key column to the task table named project_id:
Project Task
------- ----
id id
name name
project_id
This way, it will be possible to determine the project for each row in the task table. If you use this approach, in your e...
How to create a custom string representation for a class object?
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Implement __str__() or __repr__() in the class's metaclass.
class MC(type):
def __repr__(self):
return 'Wahaha!'
class C(object):
__metaclass__ = MC
print C
Use __str__ if you mean a readable stringification, use __repr__ fo...
List attributes of an object
...
>>> class new_class():
... def __init__(self, number):
... self.multi = int(number) * 2
... self.str = str(number)
...
>>> a = new_class(2)
>>> a.__dict__
{'multi': 4, 'str': '2'}
>>> a.__dict__.keys(...
Overloading Macro on Number of Arguments
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Simple as:
#define GET_MACRO(_1,_2,_3,NAME,...) NAME
#define FOO(...) GET_MACRO(__VA_ARGS__, FOO3, FOO2)(__VA_ARGS__)
So if you have these macros:
FOO(World, !) # expands to FOO2(World, !)
FOO(foo,bar,baz) # expands to FOO3(foo,bar...
How do I initialize the base (super) class?
... and 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- an...
Difference between len() and .__len__()?
Is there any difference between calling len([1,2,3]) or [1,2,3].__len__() ?
4 Answers
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How do I override __getattr__ in Python without breaking the default behavior?
I want to override the __getattr__ method on a class to do something fancy but I don't want to break the default behavior.
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Multiple levels of 'collection.defaultdict' in Python
... @ScienceFriction Anything specific that you need help with? When d[new_key] is accessed, it will call the lambda which will create a new defaultdict(int). And when d[existing_key][new_key2] is accessed, a new int will be created.
– interjay
Oct 11 '13 at 1...