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One-liner to check whether an iterator yields at least one element?
... Similarly if you need to check if the iterator is empty, one could use all(False for _ in iterator) will check if the iterator is empty. (all returns True if the iterator is empty, otherwise it stops when it sees the first False element)
– KGardevoir
Apr 3 ...
How to sort two lists (which reference each other) in the exact same way
...s problem is to use the "decorate, sort, undecorate" idiom, which is especially simple using python's built-in zip function:
>>> list1 = [3,2,4,1, 1]
>>> list2 = ['three', 'two', 'four', 'one', 'one2']
>>> list1, list2 = zip(*sorted(zip(list1, list2)))
>>> list1
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How to avoid explicit 'self' in Python?
...s leads to useful properties, such as: you can't add members which accidentally shadow non-members and thereby break code.
One extreme example: you can write a class without any knowledge of what base classes it might have, and always know whether you are accessing a member or not:
class A(some_fu...
Django: How to completely uninstall a Django app?
What is the procedure for completely uninstalling a Django app, complete with database removal?
5 Answers
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Python unittest - opposite of assertRaises?
...the correct solution in fact. The solution proposed by user9876 is conceptually flawed: if you test for the non-raising of say ValueError, but ValueError is instead raised, your test must exit with a failure condition, not an error one. On the other hand, if in running the same code you would raise ...
How do you write tests for the argparse portion of a python module? [closed]
...turn parser.parse_args(args)
Then in your main function you should just call it with:
parser = parse_args(sys.argv[1:])
(where the first element of sys.argv that represents the script name is removed to not send it as an additional switch during CLI operation.)
In your tests, you can then call...
How do you get a query string on Flask?
...ut since this answer correctly answers the question my Google search terms alluded to ('flask get request parameter') I'm up-voting it anyhow. I'm a pedant too, but I'm chalking this up to web mysticism. ????
– Michael Scheper
Jan 13 '17 at 23:45
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Separation of business logic and data access in django
...de is confusing and, after a certain time, I cease to understand what is really happening.
10 Answers
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Explaining Python's '__enter__' and '__exit__'
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Using these magic methods (__enter__, __exit__) allows you to implement objects which can be used easily with the with statement.
The idea is that it makes it easy to build code which needs some 'cleandown' code executed (think of it as a try-finally block). Some more ex...
No ConcurrentList in .Net 4.0?
...read-safe, limited subset of IList<T>: in particular, one that would allow an Add and provide random read-only access by index (but no Insert, RemoveAt, etc., and also no random write access).
This was the goal of my ConcurrentList<T> implementation. But when I tested its performance in...