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What is the difference between class and instance attributes?
...just look in each instance's __dict__ and the class's __dict__. It just usually doesn't matter very much whether immutable types are shared or not.
– abarnert
Oct 29 '14 at 22:58
1...
if A vs if A is not None:
...
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 ...
Why are Python's 'private' methods not actually private?
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The name scrambling is used to ensure that subclasses don't accidentally override the private methods and attributes of their superclasses. It's not designed to prevent deliberate access from outside.
For example:
>>> class Foo(object):
... def __init__(self):
... self....
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 ...
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.
...
How do I profile memory usage in Python?
...
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...
What is Bootstrap?
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It is an HTML, CSS, and JavaScript open-source framework (initially created by Twitter) that you can use as a basis for creating web sites or web applications.
More information and links to download
Getting started
Examples
Themes
Bootply - Bootstrap Editor and Builder
Update
The o...
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...
How to use filter, map, and reduce in Python 3
... longer return lists:
[...]
map() and filter() return iterators. If you really need a list, a quick fix is e.g. list(map(...)), but a better fix is often to use a list comprehension (especially when the original code uses lambda), or rewriting the code so it doesn’t need a list at all. Particular...
How to deal with SettingWithCopyWarning in Pandas?
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The SettingWithCopyWarning was created to flag potentially confusing "chained" assignments, such as the following, which does not always work as expected, particularly when the first selection returns a copy. [see GH5390 and GH5597 for background discussion.]
df[df['A'] > 2...