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Group by in LINQ
...:
var results = from p in persons
group p.car by p.PersonId into g
select new { PersonId = g.Key, Cars = g.ToList() };
Or as a non-query expression:
var results = persons.GroupBy(
p => p.PersonId,
p => p.car,
(key, g) => new { PersonId = key, Car...
Mutex example / tutorial? [closed]
...td::mutex m;//you can use std::lock_guard if you want to be exception safe
int i = 0;
void makeACallFromPhoneBooth()
{
m.lock();//man gets a hold of the phone booth door and locks it. The other men wait outside
//man happily talks to his wife from now....
std::cout << i <&...
Booleans, conditional operators and autoboxing
...ave in common; since null (type "the special null type") can be implicitly converted (widened) to any type, you can consider the special null type to be a "superclass" of any type (class) for the purposes of lub().
– Bert F
Apr 25 '14 at 13:03
...
How can I get the current date and time in UTC or GMT in Java?
...ccording to stackoverflow.com/questions/4123534/…, the MySQL JDBC driver converts a given java.util.Timestamp (or java.util.Date) to the server time zone.
– Derek Mahar
Dec 7 '10 at 21:02
...
Pair/tuple data type in Go
...nal exercise of the Tour of Go , I decided I needed a queue of ( string , int ) pairs. That's easy enough:
3 Answers
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Cocoa Core Data efficient way to count entities
...t subentities. Default is YES (i.e. include subentities)
NSError *err;
NSUInteger count = [moc countForFetchRequest:request error:&err];
if(count == NSNotFound) {
//Handle error
}
[request release];
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Adding a cross-reference to a subheading or anchor in another page
... builders that support cross-references.
RST, in General
The tools that convert RST files to HTML do not necessarily have a notion of collection. This is the case for instance if you rely on github to convert RST files to HTML or if you use a command line tool like rst2html. Unfortunately, the va...
A monad is just a monoid in the category of endofunctors, what's the problem?
... = μ ∘ ηT = 1 (the identity natural transformation)
With a bit of squinting you might be able to see that both of these definitions are instances of the same abstract concept.
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How do you do Impersonation in .NET?
... That link from the Dutch programmer's blog was excellent. Much more intuitive approach to impersonation than the other techniques presented.
– code4life
Aug 22 '16 at 23:26
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What is meant by immutable?
...pert wrote a blog article about this. Basically you can have objects whose interface is immutable but behind the scenes actual mutables private state (and therefore can't be shared safely between threads).
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