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if A vs if A is not None:
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The statement
if A:
will call A.__nonzero__() (see Special method names documentation) and use the return value of that function. Here's the summary:
object.__nonzero__(self)
Called to implement truth value testing and the built-in operation ...
How to decorate a class?
...2.5, is there a way to create a decorator that decorates a class? Specifically, I want to use a decorator to add a member to a class and change the constructor to take a value for that member.
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How do I run all Python unit tests in a directory?
...it test module is of the form test_*.py . I am attempting to make a file called all_test.py that will, you guessed it, run all files in the aforementioned test form and return the result. I have tried two methods so far; both have failed. I will show the two methods, and I hope someone out there ...
Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference
Given the following examples, why is outerScopeVar undefined in all cases?
6 Answers
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Making the iPhone vibrate
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Important Note: Alert of Future Deprecation.
As of iOS 9.0, the API functions description for:
AudioServicesPlaySystemSound(inSystemSoundID: SystemSoundID)
AudioServicesPlayAlertSound(inSystemSoundID: SystemSoundID)
includes the following note:
This function will be deprecated in a f...
Canvas is stretched when using CSS but normal with “width” / “height” properties
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Having an API that looks-like but is fundamentally different to another (css width, height). Wow.
– Ben Aston
Aug 28 '17 at 9:22
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How do I profile memory usage in Python?
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This one has been answered already here: Python memory profiler
Basically you do something like that (cited from Guppy-PE):
>>> from guppy import hpy; h=hpy()
>>> h.heap()
Partition of a set of 48477 objects. Total size = 3265516 bytes.
Index Count % Size % Cumulat...
JPA getSingleResult() or null
...esult() indicates it can't be found. Personally I can't stand this kind of API. It forces spurious exception handling for no real benefit. You just have to wrap the code in a try-catch block.
Alternatively you can query for a list and see if its empty. That doesn't throw an exception. Actually sinc...
How do JavaScript closures work?
...clared outside the function, regardless of when and where the function is called.
If a function was called by a function, which in turn was called by another function, then a chain of references to outer lexical environments is created. This chain is called the scope chain.
In the following code, in...
Why can't I overload constructors in PHP?
I have abandoned all hope of ever being able to overload my constructors in PHP, so what I'd really like to know is why .
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