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Null coalescing in powershell
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Powershell 7+
Powershell 7 introduces native null coalescing, null conditional assignment, and ternary operators in Powershell.
Null Coalescing
$null ?? 100 # Result is 100
"Evaluated" ?? (Expensive-Operation "Not Evaluated") # Right side here...
Trim a string based on the string length
...eviate.
This may behave incorrectly1 if your String contains Unicode codepoints outside of the BMP; e.g. Emojis. For a (more complicated) solution that works correctly for all Unicode code-points, see @sibnick's solution.
1 - A Unicode codepoint that is not on plane 0 (the BMP) is represented a...
浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
...公式吗： -2^(n-1)~2^(n-1)-1 n为整型的内存占用位数，所以int类型32位 那么就是 -(2^31)~2^31 -1 即
-2147483648~2147483647,但是为什么最小负数绝对值总比最大正数多1 ，这个问题甚至有的工作几年的程序员都模棱两可，因为没有深入思...
Where is shared_ptr?
...ss with other dependencies and I was unable to continue (given time constraints). If -std=c++11 is the trick, I can continue with confidence when I am able to return to the project. Thank you.
– hiwaylon
Aug 27 '12 at 15:24
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Why is my Spring @Autowired field null?
Note: This is intended to be a canonical answer for a common problem.
18 Answers
18
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Problems with Android Fragment back stack
...added fragments that were added with the same containerViewId and then add(int, Fragment, String) with the same arguments given here.
then what's happening is like this (I'm adding numbers to the frag to make it more clear):
// transaction.replace(R.id.detailFragment, frag1);
Transaction.remove(n...
The modulo operation on negative numbers in Python
...which is an invalid number, and we need to manually fix it up by adding 7:
int result = (2 - N) % 7;
return result < 0 ? result + 7 : result;
(See http://en.wikipedia.org/wiki/Modulo_operator for how the sign of result is determined for different languages.)
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Type hinting a collection of a specified type
...d within a homogeneous list (or other collection) for the purpose of type hinting in PyCharm and other IDEs?
5 Answers
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Find indices of elements equal to zero in a NumPy array
...make parsing the params easy. Otherwise something like np.zeros(3,0,dtype='int16') versus np.zeros(3,3,3,dtype='int16') would be annoying to implement.
– mtrw
Jan 13 '14 at 10:40
5...
Replacing NAs with latest non-NA value
...na.locf(cz, na.rm=FALSE) to keep leading NA.
– BallpointBen
May 17 '18 at 16:21
1
@BallpointBen '...