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Why does direction of index matter in MongoDB?
...d query in the same order as the index will simply return the rows sequentially in the correct order.
Finding a record in a BTree takes O(Log(n)) time. Finding a range of records in order is only OLog(n) + k where k is the number of records to return.
If the records are out of order, the cost coul...
How to convert a selection to lowercase or uppercase in Sublime Text
...eral strings selected in a file in Sublime Text and I want to convert them all to lowercase.
5 Answers
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How to require a controller in an angularjs directive
...});
Each directive will get its own instance of the controller, but this allows you to share the logic between as many components as you want.
Require a Controller
If you want to share the same instance of a controller, then you use require.
require ensures the presence of another directive an...
Does every Javascript function have to return a value?
...ow level, the return is translated into some sort of jump. If a function really returned nothing at all, there would be no way of knowing what and when to call the next function, or to call event handlers and the like.
So to recap: No, a JS function needn't return anything as far as your code goes....
Reference assignment operator in PHP, =&
...rror changes made to another, instead of copying the existing data.
It's called assignment by reference, which, to quote the manual, "means that both variables end up pointing at the same data, and nothing is copied anywhere".
The only thing that is deprecated with =& is "assigning the result ...
Junit: splitting integration test and Unit tests
...hat sort of other solutions there might be apart from annotations or physically separating the classes..
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JavaScript/regex: Remove text between parentheses
...the parentheses are in the middle of a string, the regex above will remove all the whitespace around them. This is probably not good.
– Nigel Johnson
Nov 13 '17 at 11:42
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What is a git topic branch?
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Topic branches are typically lightweight branches that you create locally and that have a name that is meaningful for you. They are where you might do work for a bug fix or feature (they're also called feature branches) that is expected to take some...
MongoDB: How to query for records where field is null or not set?
...ount({sent_at: {$exists: false}})
If its there and null, or not there at all:
db.emails.count({sent_at: null})
Refer here for querying and null
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Difference between a Postback and a Callback
I keep on hearing this words ' callback ' and ' postback ' tossed around.
What is the difference between two ?
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