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std::vector performance regression when enabling C++11
...lts are identical:
(I am compiling your original code, with container.push_back(Item());)
$ g++ -std=c++11 -O3 -flto regr.cpp && perf stat -r 10 ./a.out
Performance counter stats for './a.out' (10 runs):
35.426793 task-clock # 0.986 CPUs utilized (...
What are the differences between the threading and multiprocessing modules?
...nd a thread pool like this:
with concurrent.futures.ThreadPoolExecutor(max_workers=4) as executor:
executor.submit(job, argument)
executor.map(some_function, collection_of_independent_things)
# ...
You can even get the results of those jobs and pass them on to further jobs, wait for t...
What is the difference between 'my' and 'our' in Perl?
...ny package, so that the variable cannot be accessed in the form of $package_name::variable.
On the other hand, our variables are package variables, and thus automatically:
global variables
definitely not private
not necessarily new
can be accessed outside the package (or lexical scope) with th...
Why return NotImplemented instead of raising NotImplementedError
...
It's because __lt__() and related comparison methods are quite commonly used indirectly in list sorts and such. Sometimes the algorithm will choose to try another way or pick a default winner. Raising an exception would break out of the s...
How do I get a PHP class constructor to call its parent's parent's constructor?
.../ main class that everything inherits
class Grandpa
{
public function __construct()
{
}
}
class Papa extends Grandpa
{
public function __construct($bypass = false)
{
// only perform actions inside if not bypassing
if (!$bypass) {
}
// call Gra...
Empty set literal?
...>> print(s)
set()
this is basically a more condensed way of doing {_ for _ in ()}, but, don't do this.
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Non-alphanumeric list order from os.listdir()
...however you want. Based on what you describe,
sorted(os.listdir(whatever_directory))
Alternatively, you can use the .sort method of a list:
lst = os.listdir(whatever_directory)
lst.sort()
I think should do the trick.
Note that the order that os.listdir gets the filenames is probably complet...
Getting the name of a child class in the parent class (static context)
...ot possible. in php4 you could implement a terrible hack (examine the debug_backtrace()) but that method does not work in PHP5. references:
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edit: an example of late static binding in PHP 5.3 (mentioned in comments). note there are potential problems in it's current implementat...
How to perform OR condition in django queryset?
...
from django.db.models import Q
User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True))
via Documentation
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Filtering for empty or NULL names in a queryset
I have first_name , last_name & alias (optional) which I need to search for. So, I need a query to give me all the names that have an alias set.
...