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Hashing a dictionary?
...d make a frozenset with the dict's items and use hash():
hash(frozenset(my_dict.items()))
This is much less computationally intensive than generating the JSON string or representation of the dictionary.
UPDATE: Please see the comments below, why this approach might not produce a stable result.
...
What is the difference between .*? and .* regular expressions?
...edy, first tries to match as many . as possible.
eeeAiiZuuuuAoooZeeee
\_______________/
A.* matched, Z can't match
Since the Z doesn't match, the engine backtracks, and .* must then match one fewer .:
eeeAiiZuuuuAoooZeeee
\______________/
A.* matched, Z still can't match
This ha...
Header files for x86 SIMD intrinsics
.../x86-64 use x86intrin.h
For gcc/clang/armcc targeting ARM with NEON use arm_neon.h
For gcc/clang/armcc targeting ARM with WMMX use mmintrin.h
For gcc/clang/xlcc targeting PowerPC with VMX (aka Altivec) and/or VSX use altivec.h
For gcc/clang targeting PowerPC with SPE use spe.h
You can handle all t...
How to get the parents of a Python class?
...
Use the following attribute:
cls.__bases__
From the docs:
The tuple of base classes of a class
object.
Example:
>>> str.__bases__
(<type 'basestring'>,)
Another example:
>>> class A(object):
... pass
...
>>> ...
Finding the source code for built-in Python functions?
... particular module or function is implemented in you can usually print the __file__ attribute. Alternatively, you may use the inspect module, see the section Retrieving Source Code in the documentation of inspect.
For built-in classes and methods this is not so straightforward since inspect.getfile...
What does -> mean in Python function definitions?
...
And the information is available as a .__annotations__ attribute.
– Martijn Pieters♦
Jan 17 '13 at 13:06
9
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How to sort a list of objects based on an attribute of the objects?
... work if the object has dynamically added attributes, (if you've done self.__dict__ = {'some':'dict'} after the __init__ method). I don't know why it sould be different, though.
– tutuca
Jan 7 '13 at 20:40
...
How to make a cross-module variable?
The __debug__ variable is handy in part because it affects every module. If I want to create another variable that works the same way, how would I do it?
...
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 override the [] operator in Python?
...
You need to use the __getitem__ method.
class MyClass:
def __getitem__(self, key):
return key * 2
myobj = MyClass()
myobj[3] #Output: 6
And if you're going to be setting values you'll need to implement the __setitem__ method too,...