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Is it possible to make abstract classes in Python?
...nitions of those methods:
>>> Abstract()
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Can't instantiate abstract class Abstract with abstract methods foo
>>> class StillAbstract(Abstract):
... pass
...
>>> StillAbstr...
jsonify a SQLAlchemy result set in Flask [duplicate]
...
It seems that you actually haven't executed your query. Try following:
return jsonify(json_list = qryresult.all())
[Edit]: Problem with jsonify is, that usually the objects cannot be jsonified automatically. Even Python's datetime fails ;)
Wha...
method of iterating over sqlalchemy model's defined columns?
...l exclude SA magic attributes, but will not exclude the relations. So basically it might load the dependencies, parents, children etc, which is definitely not desirable.
But it is actually much easier because if you inherit from Base, you have a __table__ attribute, so that you can do:
for c in Jo...
How do I get the number of elements in a list?
...turns 3.
Explanation
Everything in Python is an object, including lists. All objects have a header of some sort in the C implementation.
Lists and other similar builtin objects with a "size" in Python, in particular, have an attribute called ob_size, where the number of elements in the object is...
How to invoke the super constructor in Python?
In all other languages I've worked with the super constructor is invoked implicitly. How does one invoke it in Python? I would expect super(self) but this doesn't work.
...
Find all packages installed with easy_install/pip?
Is there a way to find all Python PyPI packages that were installed with easy_install or pip? I mean, excluding everything that was/is installed with the distributions tools (in this case apt-get on Debian).
...
Creating a singleton in Python
...mple implementation:
class Singleton(type):
_instances = {}
def __call__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
return cls._instances[cls]
class Logger(object):
__meta...
What's the best way to send a signal to all members of a process group?
... And if you modify the format slightly and sort, you get to see all processes nicely grouped and beginning with (potentially) the group parent in each group: ps x -o "%r %p %y %x %c" | sort -nk1,2
– haridsv
Dec 3 '12 at 12:18
...
How to get a function name as a string?
In Python, how do I get a function name as a string, without calling the function?
12 Answers
...
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...