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Is there a simple, elegant way to define singletons? [duplicate]
...
I don't really see the need, as a module with functions (and not a class) would serve well as a singleton. All its variables would be bound to the module, which could not be instantiated repeatedly anyway.
If you do wish to use a cla...
How to read the Stock CPU Usage data
... screen, showing how much the CPU is being used. The top red bar shows overall CPU usage, and the green bar underneath it shows the CPU time spent in compositing the screen. Note: You cannot turn this feature off once it is on, without restarting the emulator. developer.android.com/tools/debugging/...
What is Type-safe?
...m:
int AddTwoNumbers(int a, int b)
{
return a + b;
}
If I tried to call that using:
int Sum = AddTwoNumbers(5, "5");
The compiler would throw an error, because I am passing a string ("5"), and it is expecting an integer.
In a loosely typed language, such as javascript, I can do the follow...
Difference between String replace() and replaceAll()
What's the difference between java.lang.String 's replace() and replaceAll() methods,
other than later uses regex? For simple substitutions like, replace . with / ,
is there any difference?
...
How to combine two or more querysets in a Django view?
...sets into a list is the simplest approach. If the database will be hit for all querysets anyway (e.g. because the result needs to be sorted), this won't add further cost.
from itertools import chain
result_list = list(chain(page_list, article_list, post_list))
Using itertools.chain is faster than...
Class with Object as a parameter
... Table to be a new-style class (as opposed to "classic" class).
In Python3 all classes are new-style classes, so this is no longer necessary.
New style classes have a few special attributes that classic classes lack.
class Classic: pass
class NewStyle(object): pass
print(dir(Classic))
# ['__doc__...
How many threads is too many?
...: measure, don't guess. One suggestion is to make it configurable and initially set it to 100, then release your software to the wild and monitor what happens.
If your thread usage peaks at 3, then 100 is too much. If it remains at 100 for most of the day, bump it up to 200 and see what happens.
Y...
Iterate over object attributes in python
...foo = 1
... bar = 'hello'
... def func(self):
... return 'call me'
...
>>> obj = Cls()
calling dir on the object gives you back all the attributes of that object, including python special attributes. Although some object attributes are callable, such as methods.
>>&...
What does functools.wraps do?
... def with_logging(*args, **kwargs):
print(func.__name__ + " was called")
return func(*args, **kwargs)
return with_logging
then when you say
@logged
def f(x):
"""does some math"""
return x + x * x
it's exactly the same as saying
def f(x):
"""does some math"""
...
How to get instance variables in Python?
Is there a built-in method in Python to get an array of all a class' instance variables? For example, if I have this code:
...