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What are enums and why are they useful?
Today I was browsing through some questions on this site and I found a mention of an enum being used in singleton pattern about purported thread safety benefits to such solution.
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C# Thread safe fast(est) counter
...ment will have better performance than lock(). Just take a look at the IL and Assembly where you will see that Increment turns into a "bus lock" statement and its variable is directly incremented (x86) or "added" to (x64).
This "bus lock" statement locks the bus to prevent another CPU from acces...
How to extract numbers from a string in Python?
...his is better than the regex example because you don't need another module and it's more readable because you don't need to parse (and learn) the regex mini-language.
This will not recognize floats, negative integers, or integers in hexadecimal format. If you can't accept these limitations, jmnas's...
What is the use of the ArraySegment class?
...
ArraySegment<T> has become a lot more useful in .NET 4.5+ and .NET Core as it now implements:
IList<T>
ICollection<T>
IEnumerable<T>
IEnumerable
IReadOnlyList<T>
IReadOnlyCollection<T>
as opposed to the .NET 4 version which implemented no interfaces...
How to initialize all members of an array to the same value?
...s that value is 0 (in which case you can omit some part of the initializer
and the corresponding elements will be initialized to 0), there's no easy way.
Don't overlook the obvious solution, though:
int myArray[10] = { 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 };
Elements with missing values will be initiali...
std::enable_if to conditionally compile a member function
I am trying to get a simple example to work to understand how to use std::enable_if . After I read this answer , I thought it shouldn't be too hard to come up with a simple example. I want to use std::enable_if to choose between two member-functions and allow only one of them to be used.
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Parse date string and change format
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convert string to datetime object
from datetime import datetime
s = "2016-03-26T09:25:55.000Z"
f = "%Y-%m-%dT%H:%M:%S.%fZ"
out = datetime.strptime(s, f)
print(out)
output:
2016-03-26 09:25:55
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Why isn't sizeof for a struct equal to the sum of sizeof of each member?
...y alignment constraints. Data structure alignment impacts both performance and correctness of programs:
Mis-aligned access might be a hard error (often SIGBUS).
Mis-aligned access might be a soft error.
Either corrected in hardware, for a modest performance-degradation.
Or corrected by emulation...
'0000-00-00 00:00:00' can not be represented as java.sql.Timestamp error
...ration:
jdbc:mysql://yourserver:3306/yourdatabase?zeroDateTimeBehavior=convertToNull
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surface plots in matplotlib
...ceforge.net/mpl_examples/mplot3d/surface3d_demo.py
here's pythonic way to convert your 3-tuples to 3 1d arrays.
data = [(1,2,3), (10,20,30), (11, 22, 33), (110, 220, 330)]
X,Y,Z = zip(*data)
In [7]: X
Out[7]: (1, 10, 11, 110)
In [8]: Y
Out[8]: (2, 20, 22, 220)
In [9]: Z
Out[9]: (3, 30, 33, 330)
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