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Why use Abstract Base Classes in Python?
...emented classes.
Long version
There is a contract between a class and its callers. The class promises to do certain things and have certain properties.
There are different levels to the contract.
At a very low level, the contract might include the name of a method or its number of parameters.
In a s...
How to remove all of the data in a table using Django
...
Inside a manager:
def delete_everything(self):
Reporter.objects.all().delete()
def drop_table(self):
cursor = connection.cursor()
table_name = self.model._meta.db_table
sql = "DROP TABLE %s;" % (table_name, )
cursor.execute(sql)
...
Replacing a 32-bit loop counter with 64-bit introduces crazy performance deviations with _mm_popcnt_
...AMD documents it and compilers don't expose it.)
(Yes, these instructions all run on the same execution unit).
This dependency doesn't just hold up the 4 popcnts from a single loop iteration. It can carry across loop iterations making it impossible for the processor to parallelize different loop...
Can local storage ever be considered secure? [closed]
...
WebCrypto
The concerns with cryptography in client-side (browser) javascript are detailed below. All but one of these concerns does not apply to the WebCrypto API, which is now reasonably well supported.
For an offline app, you must still design and implement a secure keystore.
Aside: If you ...
__FILE__ macro shows full path
....com/pipermail/cmake/2013-January/053117.html
I'm copying the tip so it's all on this page:
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__FILENAME__='\"$(subst
${CMAKE_SOURCE_DIR}/,,$(abspath $<))\"'")
If you're using GNU make, I see no reason you couldn't extend this to your own makefiles. ...
How to add a custom loglevel to Python's logging facility
...for my application, as I don't think that debug() is sufficient. Additionally log(5, msg) isn't what I want. How can I add a custom loglevel to a Python logger?
...
A python class that acts like dict
...er) instead of simply delegating to the instance's __dict__ - which essentially means you're creating two dicts for every instance.
– Aaron Hall♦
Jan 8 '17 at 0:39
8
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Django filter queryset __in for *every* item in list
...
Summary:
One option is, as suggested by jpic and sgallen in the comments, to add .filter() for each category. Each additional filter adds more joins, which should not be a problem for small set of categories.
There is the aggregation approach. This query would be shorter and...
Why does this loop produce “warning: iteration 3u invokes undefined behavior” and output more than 4
...
If during the evaluation of an expression, the result is not mathematically defined or not in the range of
representable values for its type, the behavior is undefined. [ Note: most existing implementations of C++
ignore integer overflows. Treatment of division by zero, forming a remainde...
CSRF protection with CORS Origin header vs. CSRF token
...ted.
But what about other kinds of requests - e.g. form submit? Loading a script/img/... tag? Or any other way a page can use to (legally) create a request? Or maybe some known JS hack?
The Origin header is normally only sent for XHR cross-domain requests. Image requests do not contain the header....