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How do you query for “is not null” in Mongo?
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This will return all documents with a key called "IMAGE URL", but they may still have a null value.
db.mycollection.find({"IMAGE URL":{$exists:true}});
This will return all documents with both a key called "IMAGE URL" and a non-null value.
d...
Is it possible to Turn page programmatically in UIPageViewController?
Is it possible to turn page programmatically in UIPageViewController ?
17 Answers
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php $_POST array empty upon form submission
... "WWW." The $_POST array was getting emptied in the process. So to fix it all I had to do was submit to www.domain.com
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How to enable C++11/C++0x support in Eclipse CDT?
..., find the Preprocessor Include Path and go to the Providers Tab. Deselect all except CDT GCC Builtin Compiler Settings. Then untag Share settings entries … . Add the option -std=c++11 to the text box called Command to get compiler specs.
Go to paths and symbols. Under Symbols, click restore defau...
Rounding up to next power of 2
...mon: it's the portable solution. There's no common efficient algorithm for all architectures
– phuclv
Dec 6 '13 at 9:27
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Extract value of attribute node via XPath
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With xqilla it was necessary to call xs:string. I wonder why.
– krlmlr
Jul 22 '13 at 20:00
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How is “=default” different from “{}” for default constructor and destructor?
I originally posted this as a question only about destructors, but now I'm adding consideration of the default constructor. Here's the original question:
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How to use permission_required decorators on django class-based views
...ing how the new CBVs work. My question is this, I need to require login in all the views, and in some of them, specific permissions. In function-based views I do that with @permission_required() and the login_required attribute in the view, but I don't know how to do this on the new views. Is there ...
How to change the session timeout in PHP?
...cted immediately but only whenever the session GC kicks in.
GC is a potentially expensive process, so typically the probability is rather small or even zero (a website getting huge numbers of hits will probably forgo probabilistic GC entirely and schedule it to happen in the background every X minut...
what is the unsigned datatype?
...or unsigned long long int
— float
— double
— long double
— _Bool
— float _Complex
— double _Complex
— long double _Complex
— atomic type specifier
— struct or union specifier
— enum specifier
— typedef name
So in case of unsigned int we can either writ...