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Accessing dict keys like an attribute?
...
The best way to do this is:
class AttrDict(dict):
def __init__(self, *args, **kwargs):
super(AttrDict, self).__init__(*args, **kwargs)
self.__dict__ = self
Some pros:
It actually works!
No dictionary class methods are shadowed (e.g. .keys() work just fine. Unle...
super() raises “TypeError: must be type, not classobj” for new-style class
...: pass
>>> instance = OldStyle()
>>> issubclass(instance.__class__, object)
False
and not (as in the question):
>>> isinstance(instance, object)
True
For classes, the correct "is this a new-style class" test is:
>>> issubclass(OldStyle, object) # OldStyle i...
Django: Get list of model fields?
...to get a list of all the fields defined for this model. For example, phone_number = CharField(max_length=20) . Basically, I want to retrieve anything that inherits from the Field class.
...
error C2780: \'void __cdecl std::sort(_RI,_RI,_Pr)\' : expects 3 argum...
error C2780: 'void __cdecl std::sort(_RI,_RI,_Pr)' : expects 3 arguments - 2 providedprog7.cpp(8) :error C2780:'void __cdecl std::sort(_RI,_RI,_Pr)' : expects 3 arguments - 2 provided C: Pr...prog7.cpp(8) : error C2780: 'void __cdecl std::sort(_RI,_RI,_Pr)' : expects 3 arguments - 2 provided
C:...
使用std::string作为std::map的key出错解决 - C/C++ - 清泛网 - 专注C/C++及内核技术
...0\vc\include\xstddef(180): error C2784: “bool std::operator <(const std::_Tree<_Traits> &,const std::_Tree<_Traits> &)”: 未能从“const std::string”为“const std::_Tree<_Traits> &”推导 模板 参数
1> c:\program files (x86)\microsoft visual studio 11.0\vc\include\xtree(2245...
Pandas selecting by label sometimes return Series, sometimes returns DataFrame
...using? On the latest version, I get a KeyError when I try .loc[[nonexistent_label]].
– Dan Allan
Nov 6 '14 at 16:58
2
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Python: Bind an Unbound Method?
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All functions are also descriptors, so you can bind them by calling their __get__ method:
bound_handler = handler.__get__(self, MyWidget)
Here's R. Hettinger's excellent guide to descriptors.
As a self-contained example pulled from Keith's comment:
def bind(instance, func, as_name=None):
...
Approximate cost to access various caches and main memory?
...opy of a line. But remember, Intel uses MESIF (en.wikipedia.org/wiki/MESIF_protocol) for NUMA, AMD uses MOESI. I think within a single socket, though, MESIF isn't really a thing because data comes from L3, not core->core. So it's probably more relevant for L3 cache->cache transfers across s...
STL：accumulate与自定义数据类型 - C/C++ - 清泛网 - 专注C/C++及内核技术
...mulate()的原型为(文件取自DEV-C++编译器)：
template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
_Tp accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
_BinaryOperation __binary_op)
{
// concept requirements
__glibcxx...
What does the caret operator (^) in Python do?
...
It invokes the __xor__() or __rxor__() method of the object as needed, which for integer types does a bitwise exclusive-or.
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