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What is the difference between class and instance attributes?
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Only the mutable types are shared. Like for int and str they still attached with each instances rather than class.
– Babu
Jul 17 '14 at 11:59
11
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PATH issue with pytest 'ImportError: No module named YadaYadaYada'
I used easy_install to install pytest on a mac and started writing tests for a project with a file structure likes so:
20 A...
How to save all the variables in the current python session?
...s()[key]
except TypeError:
#
# __builtins__, my_shelf, and imported modules can not be shelved.
#
print('ERROR shelving: {0}'.format(key))
my_shelf.close()
To restore:
my_shelf = shelve.open(filename)
for key in my_shelf:
globals()[key]=my_shelf[key]
my_she...
Mac zip compress without __MACOSX folder?
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When I had this problem I've done it from command line:
zip file.zip uncompressed
EDIT, after many downvotes: I was using this option for some time ago and I don't know where I learnt it, so I can't give you a better explanation. Chris Johnson's answer is correct, but ...
What is the best way to implement nested dictionaries?
...ython?
This is a bad idea, don't do it. Instead, use a regular dictionary and use dict.setdefault where apropos, so when keys are missing under normal usage you get the expected KeyError. If you insist on getting this behavior, here's how to shoot yourself in the foot:
Implement __missing__ on a di...
“Inner exception” (with traceback) in Python?
My background is in C# and I've just recently started programming in Python. When an exception is thrown I typically want to wrap it in another exception that adds more information, while still showing the full stack trace. It's quite easy in C#, but how do I do it in Python?
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How to initialize all members of an array to the same value?
...s that value is 0 (in which case you can omit some part of the initializer
and the corresponding elements will be initialized to 0), there's no easy way.
Don't overlook the obvious solution, though:
int myArray[10] = { 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 };
Elements with missing values will be initiali...
python: How do I know what type of exception occurred?
...ns, but no one seems to want to tell you why, which is essential to understanding when you can break the "rule". Here is an explanation. Basically, it's so that you don't hide:
the fact that an error occurred
the specifics of the error that occurred (error hiding antipattern)
So as long as you ...
TypeError: module.__init__() takes at most 2 arguments (3 given)
... screwy.
Change your import statement to:
from Object import ClassName
and your class definition to:
class Visitor(ClassName):
or
change your class definition to:
class Visitor(Object.ClassName):
etc
share
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Get name of current class?
...at class creation time (conceptually at the very end of the class: block), and can manipulate the class being created. I haven't tested this:
class InputAssigningMetaclass(type):
def __new__(cls, name, bases, attrs):
cls.input = get_input(name)
return super(MyType, cls).__new__...