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what does the __file__ variable mean/do?
I usually just hard-wire these with the actual path. But there is a reason for these statements that determine path at runtime, and I would really like to understand the os.path module so that I can start using it.
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Why aren't superclass __init__ methods automatically invoked?
Why did the Python designers decide that subclasses' __init__() methods don't automatically call the __init__() methods of their superclasses, as in some other languages? Is the Pythonic and recommended idiom really like the following?
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Are static class variables possible in Python?
Is it possible to have static class variables or methods in Python? What syntax is required to do this?
21 Answers
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__getattr__ on a module
...le, use a module as a context manager simply by defining __enter__ and __exit__, before those tricks broke.
Recently some historical features have made a comeback, the module __getattr__ among them, and so the existing hack (a module replacing itself with a class in sys.modules at import time) sho...
KIO4_Gradient 拓展：布局中的颜色渐变 - App Inventor 2 中文网 - 清泛IT...
...置255彻底成白色了。
暂时用拓展解决一下：https://community.appinventor.mi ... with-colors/56116/2
Difference between left join and right join in SQL Server [duplicate]
...indeed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
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Print all properties of a Python Class [duplicate]
I have a class Animal with several properties like:
6 Answers
6
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Finding what methods a Python object has
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For many objects, you can use this code, replacing 'object' with the object you're interested in:
object_methods = [method_name for method_name in dir(object)
if callable(getattr(object, method_name))]
I discovered it at diveintopython.net (Now archived). Hopefully...
What is the meaning of single and double underscore before an object name?
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Single Underscore
Names, in a class, with a leading underscore are simply to indicate to other programmers that the attribute or method is intended to be private. However, nothing special is done with the name itself.
To quote PEP-8:
_single_leading_undersc...
A python class that acts like dict
I want to write a custom class that behaves like dict - so, I am inheriting from dict .
9 Answers
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