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Will the base class constructor be automatically called?
... age of customer be 2? It seems like the base class's constructor will be called no matter what. If so, why do we need to call base at the end sometimes?
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How to list all installed packages and their versions in Python?
Is there a way in Python to list all installed packages and their versions?
11 Answers
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What new capabilities do user-defined literals add to C++?
C++11 introduces user-defined literals which will allow the introduction of new literal syntax based on existing literals ( int , hex , string , float ) so that any type will be able to have a literal presentation.
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Complete Working Sample of the Gmail Three-Fragment Animation Scenario?
...at I'll refer to as "the Gmail three-fragment animation" scenario. Specifically, we want to start with two fragments, like this:
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Exporting functions from a DLL with dllexport
...ain C exports, use a C project not C++. C++ DLLs rely on name-mangling for all the C++isms (namespaces etc...). You can compile your code as C by going into your project settings under C/C++->Advanced, there is an option "Compile As" which corresponds to the compiler switches /TP and /TC.
If you ...
Principal component analysis in Python
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Months later, here's a small class PCA, and a picture:
#!/usr/bin/env python
""" a small class for Principal Component Analysis
Usage:
p = PCA( A, fraction=0.90 )
In:
A: an array of e.g. 1000 observations x 20 variables, 1000 rows x 20 colum...
Obfuscated C Code Contest 2006. Please explain sykes2.c
...downwards). So, t is the character of __TIME__ being output.
a ends up equalling the following in binary, depending on the input t:
0 00111111
1 00101000
2 01110101
3 01111001
4 01101010
5 01011011
6 01011111
7 00101001
8 01111111
9 01111011
: 01000000
Each number is a bitmap describing the segm...
How to shuffle a std::vector?
...n Coliru
Make sure to reuse the same instance of rng throughout multiple calls to std::shuffle if you intend to generate different permutations every time!
Moreover, if you want your program to create different sequences of shuffles each time it is run, you can seed the constructor of the random e...
string sanitizer for filename
...a whitelist of characters you are happy to be used? For example, you could allow just good ol' a-z, 0-9, _, and a single instance of a period (.). That's obviously more limiting than most filesystems, but should keep you safe.
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Use numpy array in shared memory for multiprocessing
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To add to @unutbu's (not available anymore) and @Henry Gomersall's answers. You could use shared_arr.get_lock() to synchronize access when needed:
shared_arr = mp.Array(ctypes.c_double, N)
# ...
def f(i): # could be anything numpy accepts as an index such another numpy array
with ...