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How do I get the opposite (negation) of a Boolean in Python?
...ll __bool__ on the object.
So by implementing __bool__ (or __nonzero__ in Python 2) you can customize the truth value and thus the result of not:
class Test(object):
def __init__(self, value):
self._value = value
def __bool__(self):
print('__bool__ called on {!r}'.format(s...
How to move a model between two Django apps (Django 1.7)
... refer to my old answer.
First migration to remove model from 1st app.
$ python manage.py makemigrations old_app --empty
Edit migration file to include these operations.
class Migration(migrations.Migration):
database_operations = [migrations.AlterModelTable('TheModel', 'newapp_themodel')]...
Loop through all nested dictionary values?
...error:
RuntimeError: maximum recursion depth exceeded while calling a Python object
The same goes with the implementation from senderle.
Similarly, you get an infinite loop with this implementation from Fred Foo:
def myprint(d):
stack = list(d.items())
while stack:
...
Haversine Formula in Python (Bearing and Distance between two GPS points)
...
Here's a Python version:
from math import radians, cos, sin, asin, sqrt
def haversine(lon1, lat1, lon2, lat2):
"""
Calculate the great circle distance between two points
on the earth (specified in decimal degrees)
"...
Should I use Vagrant or Docker for creating an isolated environment? [closed]
I use Ubuntu for development and deployment and have a need for creating an isolated environment.
10 Answers
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Passing functions with arguments to another function in Python?
Is it possible to pass functions with arguments to another function in Python?
7 Answers
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Double Iteration in List Comprehension
In Python you can have multiple iterators in a list comprehension, like
10 Answers
10
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How to get the parents of a Python class?
How can I get the parent class(es) of a Python class?
6 Answers
6
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Concurrent.futures vs Multiprocessing in Python 3
Python 3.2 introduced Concurrent Futures , which appear to be some advanced combination of the older threading and multiprocessing modules.
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Define a lambda expression that raises an Exception
...
There is more than one way to skin a Python:
y = lambda: (_ for _ in ()).throw(Exception('foobar'))
Lambdas accept statements. Since raise ex is a statement, you could write a general purpose raiser:
def raise_(ex):
raise ex
y = lambda: raise_(Excepti...