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How do you query for “is not null” in Mongo?
...: 1 }
{ "_id" : ObjectId("544540f11b5cf91c4893eb99"), "otherField" : 2 }
Now, create the sparse index on imageUrl field:
db.foo.ensureIndex( { "imageUrl": 1 }, { sparse: true } )
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}
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Difference between private, public, and protected inheritance
...like to describe member's accessors first in my own words. If you already know this, skip to the heading "next:".
There are three accessors that I'm aware of: public, protected and private.
Let:
class Base {
public:
int publicMember;
protected:
int protectedMember;
pr...
jQuery how to bind onclick event to dynamically added HTML element [duplicate]
...
Indeed, when you are targeting known markup structures created by some other code. But here he was inserting the elements himself, and there is no clear selector for them (it's just an anchor, which there might be many of), so he would have to add additiona...
what is the difference between sendStickyBroadcast and sendBroadcast in Android
... @Kushal: "So what should be alternative for sticky broadcast now?" -- I cannot really answer that, as I do not know what your use case is. You might consider asking a new Stack Overflow question, where you describe your business requirement, explain how you were thinking of solving it ...
Cannot ping AWS EC2 instance
...h Advanced Security
Select inbound rules
4) Done! Hopefully you should now be able to ping your server.
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How does virtual inheritance solve the “diamond” (multiple inheritance) ambiguity?
...ally inherit A. D's object size is increased because it stores 2 pointers now; however there is only one A now.
So B::A and C::A are the same and so there can be no ambiguous calls from D. If you don't use virtual inheritance you have the second diagram above. And any call to a member of A the...
Initializing a list to a known number of elements in Python [duplicate]
Right now I am using a list, and was expecting something like:
9 Answers
9
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How do I deal with certificates using cURL while trying to access an HTTPS url?
...hub.com/cfg/apt-cyg/master/apt-cyg -k
and no error message. As a bonus, now I have apt-cyg installed. And ca-certificates.
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Error handling in Bash
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set -e -o pipefail -u # and know what you are doing
– Sam Watkins
Jul 3 '14 at 8:32
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What is Common Gateway Interface (CGI)?
... the parameters via standard input and standard output so the program can know where and what to look for.
The main benefit is that you can run ANY executable code from the web, given that both the webserver and the program know how CGI works. That's why you could write web programs in C or Bash wi...