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MongoDb query condition on comparing 2 fields
I have a collection T , with 2 fields: Grade1 and Grade2 , and I want to select those with condition Grade1 > Grade2 , how can I get a query like in MySQL?
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How do I expire a PHP session after 30 minutes?
I need to keep a session alive for 30 minutes and then destroy it.
15 Answers
15
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What is the difference between Numpy's array() and asarray() functions?
What is the difference between Numpy's array() and asarray() functions? When should you use one rather than the other? They seem to generate identical output for all the inputs I can think of.
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How to convert ‘false’ to 0 and ‘true’ to 1 in Python
Is there a way to convert true of type unicode to 1 and false of type unicode to 0 (in Python)?
7 Answers
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Simplest/Cleanest way to implement singleton in JavaScript?
...ake the object immutable, preventing any modification to the its structure and values.
Additionally I would like to mention that if you are using ES6, you can represent a singleton using ES Modules very easily, and you can even hold private state by declaring variables at the module scope:
// my-s...
Android Gallery on Android 4.4 (KitKat) returns different URI for Intent.ACTION_GET_CONTENT
...it is a shame google made this kind of change without proper documantation and announcement.
– user65721
Nov 17 '13 at 3:11
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Volatile boolean vs AtomicBoolean
...ranteed that every method is "atomic".
Thus, if you use an AtomicInteger and getAndAdd(int delta), you can be sure that the result will be 10. In the same way, if two threads both negate a boolean variable concurrently, with an AtomicBoolean you can be sure it has the original value afterwards, wi...
Initialization of an ArrayList in one line
... end up with is a subclass of ArrayList which has an instance initializer, and that class is created just to create one object -- that just seems like a little bit overkill to me.
What would have been nice was if the Collection Literals proposal for Project Coin was accepted (it was slated to be in...
Has Facebook sharer.php changed to no longer accept detailed parameters?
...eters in sharer.php
The sharer will no longer accept custom parameters and facebook will
pull the information that is being displayed in the preview the same
way that it would appear on facebook as a post from the url OG meta
tags.
Use dialog/feeds instead of sharer.php
https://www.face...
What are some uses of template template parameters?
... all specializations of H.
NOTE: I've been programming c++ for many years and have only needed this once. I find that it is a rarely needed feature (of course handy when you need it!).
I've been trying to think of good examples, and to be honest, most of the time this isn't necessary, but let's co...