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Update MongoDB field using value of another field
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The way we do this is by $projecting our documents and use the $concat string aggregation operator to return the concatenated string.
we From there, you then iterate the cursor and use the $set update operator to add the new field to your documents using bulk operations for maximum efficiency.
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Is 1.0 a valid output from std::generate_canonical?
...curs quite often in real-world calculations) when x is close to zero. The "extra precision" near multiples of π is generally just a side effect of that.
– Ilmari Karonen
Sep 4 '14 at 20:16
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How to JSON serialize sets?
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JSON notation has only a handful of native datatypes (objects, arrays, strings, numbers, booleans, and null), so anything serialized in JSON needs to be expressed as one of these types.
As shown in the json module docs, this conversion can be done automatically by a JSONEncoder and JSONDecoder,...
JSONP with ASP.NET Web API
..., and now I am trying to consume it using JQuery. I can get back the JSON string using Fiddler, and it seems to be ok, but because the service exists on a separate site, trying to call it with JQuery errors with the "Not Allowed". So, this is clearly a case where I need to use JSONP.
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Calling async method synchronously
...ask, which will cause your thread to block until the result is available:
string code = GenerateCodeAsync().Result;
Note: In some cases, this might lead to a deadlock: Your call to Result blocks the main thread, thereby preventing the remainder of the async code to execute. You have the followi...
Designing function f(f(n)) == -n
...oof of why such a function can't exist, for all numbers, if it doesn't use extra information(except 32bits of int):
We must have f(0) = 0. (Proof: Suppose f(0) = x. Then f(x) = f(f(0)) = -0 = 0. Now, -x = f(f(x)) = f(0) = x, which means that x = 0.)
Further, for any x and y, suppose f(x) = y. We w...
What is the proper way to re-throw an exception in C#? [duplicate]
...or, but allows you to put more context, such as an object ID, a connection string, stuff like that. Often my exception reporting tool will have 5 chained exceptions to report, each reporting more detail.
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How do I output text without a newline in PowerShell?
...our case (since you're providing informative output to the user), create a string that you can use to append output. When it's time to output it, just output the string.
Ignoring of course that this example is silly in your case but useful in concept:
$output = "Enabling feature XYZ......."
Enable...
ReSharper warns: “Static field in generic type”
...public class Test
{
public static void Main()
{
Generic<string>.Foo = 20;
Generic<object>.Foo = 10;
Console.WriteLine(Generic<string>.Foo); // 20
}
}
As you can see, Generic<string>.Foo is a different field from Generic<object>.Foo ...
Curly braces in string in PHP
What is the meaning of { } (curly braces) in string literals in PHP?
5 Answers
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