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What is a mixin, and why are they useful?
...ming Python ", Mark Lutz mentions "mixins". I'm from a C/C++/C# background and I have not heard the term before. What is a mixin?
...
How to create module-wide variables in Python? [duplicate]
... particular scope. (If you make a variable inside the Python interpreter, and then import other modules, your variable is in the outermost scope and thus global within your Python session.)
All you have to do to make a module-global variable is just assign to a name.
Imagine a file called foo.py,...
Obfuscated C Code Contest 2006. Please explain sykes2.c
...char(32 | (b & 1));
}
}
Now, note that a[b] is the same as b[a], and apply the -~ == 1+ change again:
main(int i) {
if(i != 448)
main(i+1);
i--;
if(i % 64 == 0) {
putchar('\n');
} else {
char a = (">'txiZ^(~z?"-48)[(__TIME__-i/8%8)[7]] + 1;
...
What is the purpose of python's inner classes?
...seful to only one other class then it is logical to embed it in that class and keep the two together. Nesting such "helper classes" makes their package more streamlined.
Increased encapsulation: Consider two top-level classes A and B where B needs access to members of A that would otherwise be dec...
Underscore vs Double underscore with variables and methods [duplicate]
...e class FooBar, __boo becomes _FooBar__boo; see below).
__double_leading_and_trailing_underscore__: "magic" objects or
attributes that live in user-controlled namespaces. E.g. __init__,
__import__ or __file__. Never invent such names; only use them
as documented.
Also, from Davi...
Can “using” with more than one resource cause a resource leak?
...
@WeylandYutani: What are you asking?
– SLaks
Jan 14 '14 at 16:18
9
...
Creating a singleton in Python
...bute.
A metaclass essentially decides what the definition of a class means and how to implement that definition. See for example http://code.activestate.com/recipes/498149/, which essentially recreates C-style structs in Python using metaclasses. The thread What are some (concrete) use-cases for met...
A python class that acts like dict
...ict actually contains 2 dict-instance: The 1st is the inherited container, and the 2nd is the dict holding the class-attributes - you may avoid that by using slots.
– ankostis
Mar 4 '16 at 10:37
...
How to import classes defined in __init__.py
...py
|-- helper.py
`-- settings.py
2 directories, 6 files
The command:
$ python import_submodule.py
Output:
settings
helper
Helper in lib.settings
someobject
Helper in lib.foo.someobject
# ./import_submodule.py
import fnmatch, os
from lib.settings import Values
from lib import Helper
...
Adding a Method to an Existing Object Instance
...
In Python, there is a difference between functions and bound methods.
>>> def foo():
... print "foo"
...
>>> class A:
... def bar( self ):
... print "bar"
...
>>> a = A()
>>> foo
<function foo at 0x00A98D70>
>>&g...