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Include all existing fields and add new fields to document
...The $addFields stage is equivalent to a $project stage that explicitly specifies all existing fields in the input documents and adds the new fields.
db.collection.aggregate([
{ "$addFields": { "custom_field": "$obj.obj_field1" } }
])
...
How to convert R Markdown to PDF?
...
Updated Answer (10 Feb 2013)
rmarkdown package:
There is now an rmarkdown package available on github that interfaces with Pandoc.
It includes a render function. The documentation makes it pretty clear how to convert rmarkdown to pdf among a range of other formats. This includes i...
Forward function declarations in a Bash or a Shell script?
...
This seems somewhat analogous to what if _ _ name _ _ == "_ _ main _ _": main() does in python
– Sergiy Kolodyazhnyy
Feb 13 '16 at 7:13
...
What are the differences between Autotools, Cmake and Scons?
...ugh time in the rest of this month to sort the mess out...) for work right now as I'm typing this. Apache Thrift has one of those BROKEN build systems that won't cross-compile.)
The "normal" users are actually NOT going to just do "./configure; make"- for many things, they're going to be pulling a ...
Property getters and setters
... Int {
set { _x = 2 * newValue }
get { return _x / 2 }
}
}
Specifically, in the Swift REPL:
15> var pt = Point()
pt: Point = {
_x = 0
}
16> pt.x = 10
17> pt
$R3: Point = {
_x = 20
}
18> pt.x
$R4: Int = 10
...
Start may not be called on a promise-style task. exception is coming
...ask.Run or Task.Factory.StartNew to both create and start a new Task.
So, now we know to just get rid of that pesky Start. You'll run your code and find that the message box is shown right away, not 5 seconds later, what's up with that?
Well, Task.Delay just gives you a task that will be complete...
How do I check if an element is really visible with JavaScript? [duplicate]
...
I don't know how much of this is supported in older or not-so-modern browsers, but I'm using something like this (without the neeed for any libraries):
function visible(element) {
if (element.offsetWidth === 0 || element.offsetHeig...
C# Float expression: strange behavior when casting the result float to int
...igher precision than the formal type (section 11.2.2). That's why you see different behavior on different systems: In the expression (int)(6.2f * 10), the compiler has the option of keeping the value 6.2f * 10 in a high precision intermediate form before converting to int. If it does, then the resul...
Android: Getting a file URI from a content URI?
... Check the scheme of the URI returned to you from the chooser activity. If if uri.getScheme.equals("content"), open it with a content resolver. If the uri.Scheme.equals("file"), open it using normal file methods. Either way, you'll end up with an InputStream that you can process using common code...
Can I implement an autonomous `self` member type in C++?
...
class WITH_SELF(Foo)
{
void test()
{
self foo;
}
};
If you want to derive from Foo then you should use the macro WITH_SELF_DERIVED in the following way:
class WITH_SELF_DERIVED(Bar,Foo)
{
/* ... */
};
You can even do multiple inheritance with as many base classes as you...