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What is the copy-and-swap idiom?
...s arguably the most nuanced and difficult. How should it be done? What pitfalls need to be avoided?
The copy-and-swap idiom is the solution, and elegantly assists the assignment operator in achieving two things: avoiding code duplication, and providing a strong exception guarantee.
How does it wor...
Openssl is not recognized as an internal or external command
...
Well at the place of openssl ... you have to put actually the path to your openssl folder that you have downloaded. Your actual command should look like:
keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | "C:\Users\abc\openssl\bin\openssl.exe" sha1...
How to create the most compact mapping n → isprime(n) up to a limit N?
Naturally, for bool isprime(number) there would be a data structure I could query.
I define the best algorithm , to be the algorithm that produces a data structure with lowest memory consumption for the range (1, N], where N is a constant.
Just an example of what I am looking for: I could rep...
What do 'real', 'user' and 'sys' mean in the output of time(1)?
... time; User and Sys refer to CPU time used only by the process.
Real is wall clock time - time from start to finish of the call. This is all elapsed time including time slices used by other processes and time the process spends blocked (for example if it is waiting for I/O to complete).
User is t...
Pelican 3.3 pelican-quickstart error “ValueError: unknown locale: UTF-8”
...
You could try a solution posted here or here. Basically, add some lines to your ~/.bash_profile:
export LC_ALL=en_US.UTF-8
export LANG=en_US.UTF-8
There is an outstanding bug report related to this issue. It appears that Python makes some assumptions about the format of l...
Coding Practices which enable the compiler/optimizer to make a faster program
...act.
Expect to be disappointed and to have to work very hard indeed for small performance improvements. Modern compilers for mature languages such as Fortran and C are very, very good. If you read an account of a 'trick' to get better performance out of code, bear in mind that the compiler writer...
Selecting multiple columns in a pandas dataframe
...).
df1 = df[['a', 'b']]
Alternatively, if it matters to index them numerically and not by their name (say your code should automatically do this without knowing the names of the first two columns) then you can do this instead:
df1 = df.iloc[:, 0:2] # Remember that Python does not slice inclusive of...
Relationship between SciPy and NumPy
SciPy appears to provide most (but not all [1]) of NumPy's functions in its own namespace. In other words, if there's a function named numpy.foo , there's almost certainly a scipy.foo . Most of the time, the two appear to be exactly the same, oftentimes even pointing to the same function object.
...
assertEquals vs. assertEqual in python
...as been deprecated as well:
Method Name | Deprecated alias(es)
_________________________________________________________
assertEqual() | failUnlessEqual, assertEquals
From 25.3.7.1.1. Deprecated aliases
...
How to change field name in Django REST Framework
...get_alternate_name(self, obj):
return obj.alternate_name
Additionally, you can use serializers.CharField with source attribute:
class ParkSerializer(serializers.ModelSerializer):
location = serializers.CharField(source='other_fields')
class Meta:
model = Park
fiel...