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How to implement an ordered, default dict? [duplicate]
...eredDict):
# Source: http://stackoverflow.com/a/6190500/562769
def __init__(self, default_factory=None, *a, **kw):
if (default_factory is not None and
not isinstance(default_factory, Callable)):
raise TypeError('first argument must be callable')
Ordered...
What exactly does += do in python?
...
In Python, += is sugar coating for the __iadd__ special method, or __add__ or __radd__ if __iadd__ isn't present. The __iadd__ method of a class can do anything it wants. The list object implements it and uses it to iterate over an iterable object appending each...
How to join components of a path when you are constructing a URL in Python
...e os.path at run time based on the current OS.
# os.py
import sys, errno
_names = sys.builtin_module_names
if 'posix' in _names:
# ...
from posix import *
# ...
import posixpath as path
# ...
elif 'nt' in _names:
# ...
from nt import *
# ...
import ntpath as p...
How do I get the opposite (negation) of a Boolean in Python?
... function
There are also two functions in the operator module operator.not_ and it's alias operator.__not__ in case you need it as function instead of as operator:
>>> import operator
>>> operator.not_(False)
True
>>> operator.not_(True)
False
These can be useful if yo...
浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
...减法，它会转化为1+(-1) ,因此
0000 0001
+ 1000 0001
____________________
1000 0010 …………… -2 ，1-1= -2? 这显然是不对了，所以为了避免减法运算错误，计算机大神们发明出了反码，直接用最高位表示符号位的叫做...
difference between variables inside and outside of __init__()
...
Variable set outside __init__ belong to the class. They're shared by all instances.
Variables created inside __init__ (and all other method functions) and prefaced with self. belong to the object instance.
...
Inherit docstrings in Python class inheritance
...out this a while ago, and a recipe was created. Check it out here.
"""
doc_inherit decorator
Usage:
class Foo(object):
def foo(self):
"Frobber"
pass
class Bar(Foo):
@doc_inherit
def foo(self):
pass
Now, Bar.foo.__doc__ == Bar().foo.__doc__ == Foo.foo.__doc__...
How to get instance variables in Python?
...
Every object has a __dict__ variable containing all the variables and its values in it.
Try this
>>> hi_obj = hi()
>>> hi_obj.__dict__.keys()
share...
How to set the prototype of a JavaScript object that has already been instantiated?
...
EDIT Feb. 2012: the answer below is no longer accurate. __proto__ is being added to ECMAScript 6 as "normative optional" which means it isn't required to be implemented but if it is, it must follow the given set of rules. This is currently unresolved but at least it will be offici...
How to suppress “unused parameter” warnings in C?
...
I'm using #define UNUSED(...) (void)(__VA_ARGS__) which allows me to apply this to multiple variables.
– Matthew Mitchell
Nov 13 '14 at 18:31
...