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Two single-column indexes vs one two-column index in MySQL?
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If you have two single column indexes, only one of them will be used in your example.
If you have an index with two columns, the query might be faster (you should measure). A two column index can also be used as a single col...
Animate change of view background color on Android
...ot using xml in my case, as the color is dynamic. Your solution also works if you create the TransitionDrawable by code.
– hpique
Jul 10 '10 at 9:43
2
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How to discover number of *logical* cores on Mac OS X?
...lanagan how many physical cores does the machine have and what chip is it? If it's a core i7 with 2 physical cores for example, it will show as 4 because the chip supports hyper-threading and presents itself to the OS as if it has 4 addressable cores.
– jkp
Sep...
Difference between jQuery’s .hide() and setting CSS to display: none
... is quicker than writing out .css("display", "none") , but what’s the difference and what are both of them actually doing to the HTML element?
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Logger slf4j advantages of formatting with {} instead of string concatenation
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It is about string concatenation performance. It's potentially significant if your have dense logging statements.
(Prior to SLF4J 1.7) But only two parameters are possible
Because the vast majority of logging statements have 2 or fewer parameters, so SLF4J API up to version 1.6 covers ...
C# Convert List to Dictionary
...ey, the second one picks the value.
You can play with it and make values differ from the keys, like this:
var res = list.ToDictionary(x => x, x => string.Format("Val: {0}", x));
If your list contains duplicates, add Distinct() like this:
var res = list.Distinct().ToDictionary(x => x, x...
How to send objects through bundle
...hree things:
1) You can break the object down to its constitute data, and if what's on the other end has knowledge of the same sort of object, it can assemble a clone from the serialized data. That's how most of the common types pass through bundles.
2) You can pass an opaque handle. If you are ...
git diff renamed file
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The issue with the difference between HEAD^^ and HEAD is that you have an a.txt in both commits, so just considering those two commits (which is what diff does), there is no rename, there is a copy and a change.
To detect copies, you can use -C...
Why use Ruby's attr_accessor, attr_reader and attr_writer?
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You may use the different accessors to communicate your intent to someone reading your code, and make it easier to write classes which will work correctly no matter how their public API is called.
class Person
attr_accessor :age
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end
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Sequelize, convert entity to plain object
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If I get you right, you want to add the sensors collection to the node. If you have a mapping between both models you can either use the include functionality explained here or the values getter defined on every instance. You...