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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...
Add a prefix to all Flask routes
...tant to the route at every definition. Is there a way to do this automatically?
10 Answers
...
__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. ...
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...
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...
How to get number of entries in a Lua table?
...ual, any of 3, 5 and 9 are valid results for #t. According to the manual, calling # on non-sequences is undefined. That means that any result (-1, 3, 3.14, 5, 9) is valid.
– cubuspl42
May 12 '14 at 20:08
...
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...
How to print a int64_t type in C
... hexadecimal.
cppreference.com has a full listing of available macros for all types including intptr_t (PRIxPTR). There are separate macros for scanf, like SCNd64.
A typical definition of PRIu16 would be "hu", so implicit string-constant concatenation happens at compile time.
For your code to ...
What's the difference between a Python module and a Python package?
...stem in the reference documentation: It’s important to keep in mind that all packages are modules.
– Martijn Pieters♦
Apr 23 '18 at 21:42
7
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Can't pickle when using multiprocessing Pool.map()
...nsider it "easy" or not;-) is to add the infrastructure to your program to allow such methods to be pickled, registering it with the copy_reg standard library method.
For example, Steven Bethard's contribution to this thread (towards the end of the thread) shows one perfectly workable approach to a...