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Python decorators are nothing more than a callable themselves (a function, or a class instance with a __call__ method). …

In Python 2, you cannot put a keyword argument after *args, that's a syntax error: >>> import sys >>> sys.version_info sys.version_info(major=2, minor=7, micro=8, releaselevel='final', serial=0) >>> def … the positional catch-all, then it captures the first positional argument: >>> def random_product(repeat=1, *args): return repeat, args ... >>> random_product('foo', 'bar') ('foo', ('bar',)) In Python …

In this specific case, you don't need to subclass defaultdict at all, because defaultdict is not much more than a dict subclass with an added __missing__ method. You can simply subclass LimitedDict a …

namedtuple has such a method because it itself is immutable. Other immutable types in the standard library have one too, like datetime.datetime for example. It is not a common pattern to use with mut …

This has nothing to do with encapsulation, and everything with a Python implementation detail as to when string literals produce a string object. … What is specifically happening here is that Python uses constants to store literal values used in code. Your 'the juice bar' value is such a constant. …

Shelve uses pickle to serialize objects. Pickle loads objects by name; the module and class name are stored and looked up when deserialising. The easiest way to support 'legacy' names is to simply cr …

In Python 3.3, a new type was added, types.SimpleNamespace(), and in the documentation it is described thus: The type is roughly equivalent to the following code: class SimpleNamespace: def __ … __name__, ", ".join(items)) Note the __init__ method of the type; you cannot get a better endorsement of the technique than the Python documentation. …

Python PEPs are discussed on the Python-Dev mailinglist, which anyone is free to join. There is a Gmane gateway for web reading too. … the python@mail.python.org list), and the model has worked well enough for this community. …

The feature is specifically meant for preventing accidental clashes between a parent class member and subclasses. The name is mangled by prepending it with the class name; the atribute __foo on a cla …

Importing the module doesn't waste anything; the module is always fully imported (into the sys.modules mapping), so whether you use import sys or from sys import argv makes no odds. The only differenc …

The multiprocessing module on the other hand, is intended to make distributing work across multiple python processes as easy as using threads for the same kind of work. …

I've been deploying python web applications for years now, and this has rarely been a problem. … tool like buildout gives you another avenue to build a fully re-playable deployment configuration, and not only can you pin your library versions with it, you can instruct buildout to never install a python …

You definitely can use duck typing here, although I'm not sure why you want to accept both a dictionary and a string in this case. I'd ask for forgiveness instead of permission in this case: try: …

Sure, that's quite simple to do. Just take the sum of both dominance values and take a random.randrange() value of these. If that value is lower than the dominance value of parent A, you picked that …

Mostly, Singletons in python are replaced with a module. Modules in python are by their very nature Singletons; the python interpreter creates these once and once only. … All other patterns in Design Patters I've used in Python at one time or another, and you'll find examples of them throughout the Python standard library and in Python itself. …