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MongoDB: Combine data from multiple collections into one..how?
..., reduce;
db.users_comments.remove();
// setup sample data - wouldn't actually use this in production
db.users.remove();
db.comments.remove();
db.users.save({firstName:"Rich",lastName:"S",gender:"M",country:"CA",age:"18"});
db.users.save({firstName:"Rob",lastName:"M",gender:"M",country:"US",age:"25...
What exactly does Perl's “bless” do?
...to a hash (most common case), to an array (not so common), to a scalar (usually this indicates an inside-out object), to a regular expression, subroutine or TYPEGLOB (see the book Object Oriented Perl: A Comprehensive Guide to Concepts and Programming Techniques by Damian Conway for useful examples)...
__proto__ VS. prototype in JavaScript
...x = x;
this.y = y;
}
var myPoint = new Point();
// the following are all true
myPoint.__proto__ == Point.prototype
myPoint.__proto__.__proto__ == Object.prototype
myPoint instanceof Point;
myPoint instanceof Object;
Here Point is a constructor function, it builds an object (data structure) p...
Can I Replace Apache with Node.js?
...l suspects (Apache, MySQL, and PHP). Since the time this website was originally launched, it has evolved quite a bit and now I'd like to do fancier things with it—namely real-time notifications. From what I've read, Apache handles this poorly. I'm wondering if I can replace just Apache with Node.j...
How can I filter a date of a DateTimeField in Django?
...
Much better than all of the other answers here, thanks!
– Kin
Jan 6 '14 at 17:06
...
Combining C++ and C - how does #ifdef __cplusplus work?
...f legacy C code. We've started writing in C++, with the intent to eventually convert the legacy code, as well. I'm a little confused about how the C and C++ interact. I understand that by wrapping the C code with extern "C" the C++ compiler will not mangle the C code's names, but I'm no...
Why do we need extern “C”{ #include } in C++?
...
C and C++ are superficially similar, but each compiles into a very different set of code. When you include a header file with a C++ compiler, the compiler is expecting C++ code. If, however, it is a C header, then the compiler expects the data cont...
Count character occurrences in a string in C++
...
Small note, but the return type is typically signed. For some reason std::count returns type iterator_traits<InputIt>::difference_type, which for most standard containers is std::ptrdiff_t, not std::size_t.
...
What does $_ mean in PowerShell?
...
This is the variable for the current value in the pipe line, which is called $PSItem in Powershell 3 and newer.
1,2,3 | %{ write-host $_ }
or
1,2,3 | %{ write-host $PSItem }
For example in the above code the %{} block is called for every value in the array. The $_ or $PSItem variable ...
Are parallel calls to send/recv on the same socket valid?
...tions, so assuming you're talking about POSIX send/recv then yes, you can call them simultaneously from multiple threads and things will work.
This doesn't necessarily mean that they'll be executed in parallel -- in the case of multiple sends, the second will likely block until the first completes....