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'is' versus try cast with null check
...// only one cast
if (myObjRef != null)
{
// myObjRef is already MyType and doesn't need to be cast again
...
}
C# 7.0 supports a more compact syntax using pattern matching:
if (myObj.myProp is MyType myObjRef)
{
...
}
...
switch / pattern matching idea
I've been looking at F# recently, and while I'm not likely to leap the fence any time soon, it definitely highlights some areas where C# (or library support) could make life easier.
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How to close Android application?
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Android has a mechanism in place to close an application safely per its documentation. In the last Activity that is exited (usually the main Activity that first came up when the application started) just place a couple of li...
Which, if any, C++ compilers do tail-recursion optimization?
...t it would work perfectly well to do tail-recursion optimization in both C and C++, yet while debugging I never seem to see a frame stack that indicates this optimization. That is kind of good, because the stack tells me how deep the recursion is. However, the optimization would be kind of nice as w...
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jumpserver-华为云免费堡垒机解决方案一、环境CentOS 6.x x86_64 minivi etc hostsvi etc sysconfig networkservice iptables stopchkconfig iptables off关闭SELinu...一、环境
CentOS 6.x x86_64 mini
vi /etc/hosts
vi /etc/sysconfig/network
service iptables stop
chkco...
How to implement classic sorting algorithms in modern C++?
The std::sort algorithm (and its cousins std::partial_sort and std::nth_element ) from the C++ Standard Library is in most implementations a complicated and hybrid amalgamation of more elementary sorting algorithms , such as selection sort, insertion sort, quick sort, merge sort, or heap sort....
Copying text to the clipboard using Java
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This works for me and is quite simple:
Import these:
import java.awt.datatransfer.StringSelection;
import java.awt.Toolkit;
import java.awt.datatransfer.Clipboard;
And then put this snippet of code wherever you'd like to alter the clipboar...
Print a file's last modified date in Bash
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You can use the
stat
command
stat -c %y "$entry"
More info
%y time of last modification, human-readable
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How to insert a newline in front of a pattern?
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This works in bash and zsh, tested on Linux and OS X:
sed 's/regexp/\'$'\n/g'
In general, for $ followed by a string literal in single quotes bash performs C-style backslash substitution, e.g. $'\t' is translated to a literal tab. Plus, sed ...
What guarantees are there on the run-time complexity (Big-O) of LINQ methods?
I've recently started using LINQ quite a bit, and I haven't really seen any mention of run-time complexity for any of the LINQ methods. Obviously, there are many factors at play here, so let's restrict the discussion to the plain IEnumerable LINQ-to-Objects provider. Further, let's assume that any...