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Retrieve only the queried element in an object array in MongoDB collection
...r to filter an array during projection, which has the benefit of including all matches, instead of just the first one.
db.test.aggregate([
// Get just the docs that contain a shapes element where color is 'red'
{$match: {'shapes.color': 'red'}},
{$project: {
shapes: {$filter: {
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Format in kotlin string templates
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edited Oct 20 '19 at 14:11
weston
49.5k1818 gold badges121121 silver badges188188 bronze badges
answer...
Passing parameters to addTarget:action:forControlEvents
...wsDetails: method here. You just create a selector to make button able to call it when certain action occurs (touch up in your case). Controls can use 3 types of selectors to respond to actions, all of them have predefined meaning of their parameters:
with no parameters
action:@selector(switchToN...
Relation between CommonJS, AMD and RequireJS?
...hingElse = function() { return someModule.doSomething() + "bar"; };
Basically, CommonJS specifies that you need to have a require() function to fetch dependencies, an exports variable to export module contents and a module identifier (which describes the location of the module in question in relat...
What does O(log n) mean exactly?
...g that the size of the input affects the growth of the algorithm proportionally...and the same goes for, for example, quadratic time O(n2) etc..even algorithms, such as permutation generators, with O(n!) times, that grow by factorials.
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How can I use pointers in Java?
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All objects in Java are references and you can use them like pointers.
abstract class Animal
{...
}
class Lion extends Animal
{...
}
class Tiger extends Animal
{
public Tiger() {...}
public void growl(){...}
}
Tiger fi...
How to create user for a db in postgresql? [closed]
I have installed PostgreSQL 8.4 on my CentOS server and connected to root user from shell and accessing the PostgreSQL shell.
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Version number comparison in Python
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Now you've merged all the good ideas from the others into your solution ... :-P still, this is pretty much what I'd do after all. I'll accept this answer. Thanks, everyone
– Johannes Charra
Nov 11 '09 at ...
Replace new lines with a comma delimiter with Notepad++?
... or anything else:
Click Edit -> Blank Operations -> EOL to space
[All the items should now be in a single line separated by a 'space']
Select any 'space' and do a Replace All (by ',')
share
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What is the difference between dict.items() and dict.iteritems() in Python2?
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It's part of an evolution.
Originally, Python items() built a real list of tuples and returned that. That could potentially take a lot of extra memory.
Then, generators were introduced to the language in general, and that method was reimplemented as an ite...