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Find MongoDB records where array field is not empty
All of my records have a field called "pictures". This field is an array of strings.
11 Answers
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Can I write a CSS selector selecting elements NOT having a certain class or attribute?
I would like to write a CSS selector rule that selects all elements that don't have a certain class. For example, given the following HTML:
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What is the difference between char s[] and char *s?
...puts the literal string in read-only memory and copies the string to newly allocated memory on the stack. Thus making
s[0] = 'J';
legal.
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How can mixed data types (int, float, char, etc) be stored in an array?
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@texasbruce also called a "tagged union". I'm using this technique too in my own language. ;)
– user529758
Sep 2 '13 at 16:50
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Measuring the distance between two coordinates in PHP
...rn $miles;
}
}
results :
echo distance(32.9697, -96.80322, 29.46786, -98.53506, "M") . " Miles<br>";
echo distance(32.9697, -96.80322, 29.46786, -98.53506, "K") . " Kilometers<br>";
echo distance(32.9697, -96.80322, 29.46786, -98.53506, "N") . " Nautical Miles<br>";
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What are the applications of binary trees?
...ningless - they are not a data structure, but a family of data structures, all with different performance characteristics. While it is true that unbalanced binary trees perform much worse than self-balancing binary trees for searching, there are many binary trees (such as binary tries) for which "b...
Linq to Entities - SQL “IN” clause
...sing LINQ, one uses query syntax and the other uses method syntax. Essentially, they are the same and could be used interchangeably depending on your preference:
Query Syntax:
var selected = from u in users
where new[] { "Admin", "User", "Limited" }.Contains(u.User_Rights)
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Check if a variable is a string in JavaScript
...ing both typeof and instanceof feels like good advice if your code may be called by others'. @MarkAmery's postmessage edge case matters if you're asking "what was I just postmessaged?" - but you'd expect that to be handled at the interface and not allowed to propagate. Elsewhere, it seems correct t...
Why do we need virtual functions in C++?
... a rat."
So far so good, right? Animals eat generic food, cats eat rats, all without virtual.
Let's change it a little now so that eat() is called via an intermediate function (a trivial function just for this example):
// This can go at the top of the main.cpp file
void func(Animal *xyz) { xyz-...
How to get string objects instead of Unicode from JSON?
...unicode strings, then recurses through the entire decoded value to convert all strings to byte strings. This has a couple of undesirable effects:
A copy of the entire decoded structure gets created in memory
If your JSON object is really deeply nested (500 levels or more) then you'll hit Python's ...