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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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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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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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get current url in twig template?

...ttributes.get('_route_params')) %} The app global view variable contains all sorts of useful shortcuts, such as app.session and app.security.token.user, that reference the services you might use in a controller. share ...
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How to avoid circular imports in Python? [duplicate]

....py Types of circular import problems Circular import dependencies typically fall into two categories depending on what you're trying to import and where you're using it inside each module. (And whether you're using python 2 or 3). 1. Errors importing modules with circular imports In some cases...
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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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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 ...