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Can't pickle when using multiprocessing Pool.map()

...nsider it "easy" or not;-) is to add the infrastructure to your program to allow such methods to be pickled, registering it with the copy_reg standard library method. For example, Steven Bethard's contribution to this thread (towards the end of the thread) shows one perfectly workable approach to a...
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What exactly are iterator, iterable, and iteration?

...loop, or map, or a list comprehension, etc. in Python, the next method is called automatically to get each item from the iterator, thus going through the process of iteration. A good place to start learning would be the iterators section of the tutorial and the iterator types section of the standar...
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A python class that acts like dict

...er) instead of simply delegating to the instance's __dict__ - which essentially means you're creating two dicts for every instance. – Aaron Hall♦ Jan 8 '17 at 0:39 8 ...
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Django filter queryset __in for *every* item in list

... Summary: One option is, as suggested by jpic and sgallen in the comments, to add .filter() for each category. Each additional filter adds more joins, which should not be a problem for small set of categories. There is the aggregation approach. This query would be shorter and...
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How do I determine the size of an object in Python?

...turn the size of an object in bytes. The object can be any type of object. All built-in objects will return correct results, but this does not have to hold true for third-party extensions as it is implementation specific. Only the memory consumption directly attributed to the object is accounted for...
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Accessing dict keys like an attribute?

...__init__(*args, **kwargs) self.__dict__ = self Some pros: It actually works! No dictionary class methods are shadowed (e.g. .keys() work just fine. Unless - of course - you assign some value to them, see below) Attributes and items are always in sync Trying to access non-existent key as an...
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How to create module-wide variables in Python? [duplicate]

... Here is what is going on. First, the only global variables Python really has are module-scoped variables. You cannot make a variable that is truly global; all you can do is make a variable in a particular scope. (If you make a variable inside the Python interpreter, and then import other mo...
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How to print a int64_t type in C

... hexadecimal. cppreference.com has a full listing of available macros for all types including intptr_t (PRIxPTR). There are separate macros for scanf, like SCNd64. A typical definition of PRIu16 would be "hu", so implicit string-constant concatenation happens at compile time. For your code to ...
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Evaluating a mathematical expression in a string

...p://pyparsing.wikispaces.com/message/view/home/15549426 ''' __note__ = ''' All I've done is rewrap Paul McGuire's fourFn.py as a class, so I can use it more easily in other places. ''' class NumericStringParser(object): ''' Most of this code comes from the fourFn.py pyparsing example ...
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What integer hash function are good that accepts an integer hash key?

...mple) and has no common factors with it. This way the hash function covers all your hash space uniformly. Edit: The biggest disadvantage of this hash function is that it preserves divisibility, so if your integers are all divisible by 2 or by 4 (which is not uncommon), their hashes will be too. Thi...