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Difference between Django's annotate and aggregate methods?
...rage_price': 34.35}
Returns a dictionary containing the average price of all books in the queryset.
Annotation
>>> q = Book.objects.annotate(num_authors=Count('authors'))
>>> q[0].num_authors
2
>>> q[1].num_authors
1
q is the queryset of books, but each book has been...
How efficient is locking an unlocked mutex? What is the cost of a mutex?
... access to the object happens often, then multiple locks would increase parallelism. At the cost of maintainability, since more locking means more debugging of the locking.
How efficient is it to lock a mutex? I.e. how much assembler instructions are there likely and how much time do they take (...
What's the difference between “git reset” and “git checkout”?
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git reset is specifically about updating the index, moving the HEAD.
git checkout is about updating the working tree (to the index or the specified tree). It will update the HEAD only if you checkout a branch (if not, you end up with a detached H...
Calling a function when ng-repeat has finished
What I am trying to implement is basically a "on ng repeat finished rendering" handler. I am able to detect when it is done but I can't figure out how to trigger a function from it.
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Is C++ context-free or context-sensitive?
... is (probably) Turing-complete, since it shows a program which is syntactically correct if and only if a given integer is prime.
So I assert that C++ is neither context-free nor context-sensitive.
If you allow arbitrary symbol sequences on both sides of any production, you produce an Type-0 gramma...
Auto-expanding layout with Qt-Designer
... QVBoxLayout should now stretch to fit the window and will resize automatically when the entire window is resized.
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Function to return only alpha-numeric characters from string?
...ake an input string and return a sanitized version of it by stripping away all special characters leaving only alpha-numeric.
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Powershell equivalent of bash ampersand (&) for forking/running background processes
...file.txt is in the current directory.
The output is not displayed automatically. You need to run Receive-Job with the ID of the job as parameter.
NOTE: Regarding your initial example, "bg sleep 30" would not work because sleep is a Powershell commandlet. Start-Process only works when you actually ...
How to version REST URIs
...resource is returning some variant of application/vnd.yourcompany.user+xml all you need to do is create support for a new application/vnd.yourcompany.userV2+xml media type and through the magic of content negotiation your v1 and v2 clients can co-exist peacefully.
In a RESTful interface, the closes...
How to check command line parameter in “.bat” file?
...gq bla2"
The syntax of the command is incorrect.
The script won't run at all. Same for args.bat:
D:\>args bla2"
The syntax of the command is incorrect.
But what do I get, when the number of "-characters "matches" (i.e. - is even), in such a case:
D:\>args bla2" "bla3
bla2" "bla3
Done.
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