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What does the “yield” keyword do?
...ou create the method of the node object that will return the generator
def _get_child_candidates(self, distance, min_dist, max_dist):
# Here is the code that will be called each time you use the generator object:
# If there is still a child of the node object on its left
# AND if the d...
super() raises “TypeError: must be type, not classobj” for new-style class
...: pass
>>> instance = OldStyle()
>>> issubclass(instance.__class__, object)
False
and not (as in the question):
>>> isinstance(instance, object)
True
For classes, the correct "is this a new-style class" test is:
>>> issubclass(OldStyle, object) # OldStyle i...
Is gcc's __attribute__((packed)) / #pragma pack unsafe?
...
Yes, __attribute__((packed)) is potentially unsafe on some systems. The symptom probably won't show up on an x86, which just makes the problem more insidious; testing on x86 systems won't reveal the problem. (On the x86, misalig...
python: How do I know what type of exception occurred?
...pe {0} occurred. Arguments:\n{1!r}"
message = template.format(type(ex).__name__, ex.args)
print message
Make sure message is brought to the attention of the user in a hard-to-miss way! Printing it, as shown above, may not be enough if the message is buried in lots of other messages. Failin...
How to set the prototype of a JavaScript object that has already been instantiated?
...
EDIT Feb. 2012: the answer below is no longer accurate. __proto__ is being added to ECMAScript 6 as "normative optional" which means it isn't required to be implemented but if it is, it must follow the given set of rules. This is currently unresolved but at least it will be offici...
How does the @property decorator work in Python?
...is just syntactic sugar; the syntax:
@property
def foo(self): return self._foo
really means the same thing as
def foo(self): return self._foo
foo = property(foo)
so foo the function is replaced by property(foo), which we saw above is a special object. Then when you use @foo.setter(), what you ...
How to get a reference to current module's attributes in Python
...he way I typically see this done is like this:
import sys
dir(sys.modules[__name__])
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What is __pycache__?
... it to bytecode first (this is an oversimplification) and stores it in the __pycache__ folder. If you look in there you will find a bunch of files sharing the names of the .py files in your project's folder, only their extensions will be either .pyc or .pyo. These are bytecode-compiled and optimized...
Does Python have a string 'contains' substring method?
...
Under the hood, Python will use __contains__(self, item), __iter__(self), and __getitem__(self, key) in that order to determine whether an item lies in a given contains. Implement at least one of those methods to make in available to your custom type.
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What is a None value?
... this book?because his name is Jason R. Briggs.
– The_Diver
Oct 20 '13 at 18:52
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