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Is there a __CLASS__ macro in C++?
Is there a __CLASS__ macro in C++ which gives the class name similar to __FUNCTION__ macro which gives the function name
...
What __init__ and self do on Python?
...
In this code:
class A(object):
def __init__(self):
self.x = 'Hello'
def method_a(self, foo):
print self.x + ' ' + foo
... the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidd...
How do I get the opposite (negation) of a Boolean in Python?
... function
There are also two functions in the operator module operator.not_ and it's alias operator.__not__ in case you need it as function instead of as operator:
>>> import operator
>>> operator.not_(False)
True
>>> operator.not_(True)
False
These can be useful if yo...
How to join components of a path when you are constructing a URL in Python
...e os.path at run time based on the current OS.
# os.py
import sys, errno
_names = sys.builtin_module_names
if 'posix' in _names:
# ...
from posix import *
# ...
import posixpath as path
# ...
elif 'nt' in _names:
# ...
from nt import *
# ...
import ntpath as p...
Does Python have an ordered set?
... the signature for .union doesn't match that of set, but since it includes __or__ something similar can easily be added:
@staticmethod
def union(*sets):
union = OrderedSet()
union.union(*sets)
return union
def union(self, *sets):
for set in sets:
self |= set
...
Class method differences in Python: bound, unbound and static
... and unbound methods.
Basically, a call to a member function (like method_one), a bound function
a_test.method_one()
is translated to
Test.method_one(a_test)
i.e. a call to an unbound method. Because of that, a call to your version of method_two will fail with a TypeError
>>> a_tes...
What exactly are iterator, iterable, and iteration?
...and iterator have specific meanings.
An iterable is an object that has an __iter__ method which returns an iterator, or which defines a __getitem__ method that can take sequential indexes starting from zero (and raises an IndexError when the indexes are no longer valid). So an iterable is an object...
Create a custom event in Java
...else in the package
interface ThrowListener {
public void Catch();
}
/*_____________________________________________________________*/class Thrower {
//list of catchers & corresponding function to add/remove them in the list
List<ThrowListener> listeners = new ArrayList<ThrowLis...
C/C++ line number
...
You should use the preprocessor macro __LINE__ and __FILE__. They are predefined macros and part of the C/C++ standard. During preprocessing, they are replaced respectively by a constant string holding an integer representing the current line number and by the cu...
Ruby send vs __send__
I understand the concept of some_instance.send but I'm trying to figure out why you can call this both ways. The Ruby Koans imply that there is some reason beyond providing lots of different ways to do the same thing. Here are the two examples of usage:
...