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Coalesce function for PHP?
...HP 7 introduced a real coalesce operator:
echo $_GET['doesNotExist'] ?? 'fallback'; // prints 'fallback'
If the value before the ?? does not exists or is null the value after the ?? is taken.
The improvement over the mentioned ?: operator is, that the ?? also handles undefined variables without...
搭建高可用mongodb集群（二）—— 副本集 - 大数据 & AI - 清泛网 - 专注C/...
...(config);
#输出成功
{
"info" : "Config now saved locally. Should come online in about a minute.",
"ok" : 1
}
#查看日志，副本集启动成功后，138为主节点PRIMARY，136、137为副本节点SECONDARY。
Sun Dec 29 20:26:13.842 [conn3] replSet repl...
Splitting templated C++ classes into .hpp/.cpp files--is it possible?
...the implementation of a template class in a separate cpp file and compile. All the ways to do so, if anyone claims, are workarounds to mimic the usage of separate cpp file but practically if you intend to write a template class library and distribute it with header and lib files to hide the implemen...
List changes unexpectedly after assignment. How do I clone or copy it to prevent this?
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With new_list = my_list, you don't actually have two lists. The assignment just copies the reference to the list, not the actual list, so both new_list and my_list refer to the same list after the assignment.
To actually copy the list, you have various possibilit...
Create subdomains on the fly with .htaccess (PHP)
...ches[1])) {
$subdomain = $matches[1];
}
I have used regex here to to allow for people hitting your site via www.subdomain.example.org or subdomain.example.org.
If you never anticipate having to deal with www. (or other subdomains) then you could simply use a substring like so:
$subdomain = s...
C++ equivalent of java's instanceof
...nceof) you'd better ask yourself whether it's a necessary thing. It's generally a sign of poor design.
Typical workarounds is putting the special behaviour for the class you are checking for into a virtual function on the base class or perhaps introducing something like a visitor where you can int...
Get local IP address
...sing Geraldo H Answer, but if anyone is using this, you may want to remove all ips that ends with 1, so it will remove loopback and virtualbox/vmware default ips
– Leonardo Xavier
Jun 23 '15 at 13:03
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How to generate JAXB classes from XSD?
...d we return a lot of XML. With this we decided to use JAXB. So far, we manually coded the Models for the XML.
10 Answers
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How do I access command line arguments in Python?
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Python tutorial explains it:
import sys
print(sys.argv)
More specifically, if you run python example.py one two three:
>>> import sys
>>> print(sys.argv)
['example.py', 'one', 'two', 'three']
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How do I remove a property from a JavaScript object?
...t object, then that object will, of course, not be garbage collected until all references to it have disappeared.
delete will only work on properties whose descriptor marks them as configurable.
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