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Instance attribute attribute_name defined outside __init__
.... We expect to find all the attributes an instance may have by reading its __init__ method.
You may still want to split initialization into other methods though. In such case, you can simply assign attributes to None (with a bit of documentation) in the __init__ then call the sub-initialization met...
Django 1.7 - makemigrations not detecting changes
... out) listed in the documentation:
python manage.py makemigrations your_app_label
The documentation does not make it obvious that you need to add the app label to the command, as the first thing it tells you to do is python manage.py makemigrations which will fail. The initial migration is don...
How can I recover the return value of a function passed to multiprocessing.Process?
... For example like this:
import multiprocessing
def worker(procnum, return_dict):
'''worker function'''
print str(procnum) + ' represent!'
return_dict[procnum] = procnum
if __name__ == '__main__':
manager = multiprocessing.Manager()
return_dict = manager.dict()
jobs = []
...
What does $_ mean in PowerShell?
...ich is called $PSItem in Powershell 3 and newer.
1,2,3 | %{ write-host $_ }
or
1,2,3 | %{ write-host $PSItem }
For example in the above code the %{} block is called for every value in the array. The $_ or $PSItem variable will contain the current value.
...
Length of generator output [duplicate]
...
The easiest way is probably just sum(1 for _ in gen) where gen is your generator.
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os.path.dirname(__file__) returns empty
...get the dirname of the absolute path, use
os.path.dirname(os.path.abspath(__file__))
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Accessing Object Memory Address
When you call the object.__repr__() method in Python you get something like this back:
9 Answers
...
How do I flag a method as deprecated in Objective-C 2.0?
...x is provided to mark methods as deprecated:
@interface SomeClass
-method __attribute__((deprecated));
@end
or:
#include <AvailabilityMacros.h>
@interface SomeClass
-method DEPRECATED_ATTRIBUTE; // or some other deployment-target-specific macro
@end
...
Can a dictionary be passed to django models on create?
...our model is called MyModel:
# create instance of model
m = MyModel(**data_dict)
# don't forget to save to database!
m.save()
As for your second question, the dictionary has to be the final argument. Again, extra and extra2 should be fields in the model.
m2 =MyModel(extra='hello', extra2='world'...
How can I create a copy of an object in Python?
... get a copy method (in 2, you'd use a slice to make a copy):
>>> a_list = list('abc')
>>> a_copy_of_a_list = a_list.copy()
>>> a_copy_of_a_list is a_list
False
>>> a_copy_of_a_list == a_list
True
Shallow Copies
Shallow copies are just copies of the outermost cont...